Jaw Shaving Surgery Risks: Lip Numbness, Bleeding, Uneven Angles and When to Wait

Hello, I'm Dr. Im Young Min, Chief Director at VG Plastic Surgery in Seoul and a board-certified plastic surgeon trained at Seoul St. Mary's Hospital.

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Im Young Min

Chief Director · Board-certified in Plastic Surgery

• — Ph.D. in Medicine
• — Internship and residency, Seoul St. Mary's Hospital
• — Board-certified plastic surgeon, Seoul St. Mary's Hospital

Two things here bear directly on those risks. Before facial contouring, the nerves and bone thickness are mapped on CT, because bone does not grow back and anything that doesn't need to go should stay. And three board-certified anesthesiologists work here full time and never operate, so one of them watches your blood pressure, pulse and breathing from the first injection until you're awake.

If a surgeon at home has already called your jaw a difficult one, send a front photo and a side photo on WhatsApp, along with any panoramic X-ray or CT you already have, and ask whether your width looks like bone or muscle. A medical interpreter for your language is provided at no extra charge, so you can ask it in your own words.

Why does the lower lip go numb after jaw shaving?

Inside each half of your lower jaw runs a canal carrying the inferior alveolar nerve. It travels forward under the teeth and comes out through a small opening below the premolars, where it becomes the mental nerve and gives feeling to the lower lip and chin. Jaw shaving removes bone from the angle and the outer surface of the lower jaw, so the closer that canal sits to the bone being taken, the less margin there is.

Most numbness doesn't come from cutting the nerve. It comes from stretching and pressure while the soft tissue is held back, or from swelling around the canal afterwards, and that kind usually recovers as the nerve settles. A review of 588 lower-jaw contouring operations, published in Plastic and Reconstructive Surgery Global Open in 2014, found that changes in sensation were the most common complication, at about 6.5 percent.

In 4.93 percent of the cases feeling came back within six months; in 1.53 percent it was still not normal after a year.

Of all the jaw shaving surgery risks, that last figure is the one I want you to weigh. It's small, but it isn't zero, and a numb patch on the lip is something you notice every time you drink from a cup. The review's author advised keeping the course of the nerve canal in mind on imaging and cutting bone carefully along it.

On a CT, the first question I'd ask is how far your canal sits from the outer surface and the lower border at the angle, because that distance sets how much bone can come off safely.

Say you're 34, living in Vancouver, with a square lower face you've disliked since your twenties. A surgeon at home looked at a panoramic X-ray, said your nerve sits low, and suggested you leave the bone alone. That doesn't close the door on surgery, and it isn't a reason to look for someone who'll simply say yes.

It means the plan has to be drawn around your nerve: a smaller reduction at the angle, or a curve that stays above the canal's path, with a result that's quieter than a photo you've saved. If the safe amount of bone wouldn't change what bothers you, I'd tell you so before you book a flight.

The same scan is why a jaw quote can move once the images are read, which I've explained in why a jaw shaving quote can change after CT.

If you have a panoramic X-ray or CT from home, send a clear photo of it or the file itself on WhatsApp with the dates you could travel, and ask how close the nerve canal looks to your jaw angle.

Bleeding, swelling and infection in the first two weeks

The angle of the jaw sits close to the facial artery and the veins behind the jaw, which is why bleeding is the risk surgeons watch most in the first hours. Most bleeding is controlled during the operation. The danger is a collection of blood under the tissue afterwards, which swells one side quickly and, if large, can press toward the airway.

A 2017 case report in the Annals of Medicine and Surgery described this situation: bleeding after a cosmetic lower-jaw bone operation done as office day surgery, which needed a second operation in hospital. The point of that report is the first night: after bone work on the jaw, spend it where someone can act quickly.

Swelling is expected and is usually heaviest in the first several days before it slowly settles. For a while the face often looks wider than before surgery, which unsettles people who expected to see a narrower jaw at once. Stiffness when opening your mouth is common early on.

Infection is less common. In the 588-case review, infections within the first two weeks appeared in about 3 percent of cases in its results, and most cleared with treatment. Because the incisions for angle reduction are usually made inside the mouth, keeping the mouth clean, rinsing after meals and not smoking matter more here than with surgery through the skin.

How many days to stay in Seoul before flying is something to settle with your surgeon at the consultation. Leave a spare day in your plans in case the swelling is slow to come down.

Can jaw shaving leave my face uneven or sagging?

Some difference between the two sides is normal in every face, and surgery can make it more or less visible. The problems people notice after jaw reduction are usually one of three: one angle taken further than the other, a visible step where the cut ends along the jawline, or a jaw so smoothed that it no longer reads as a jaw.

A long curved reduction that blends the angle into the body of the jaw avoids the step, and whether you need the angle alone or the long curve is a separate decision I've covered in jaw angle reduction versus long-curve reduction.

Sagging soft tissue depends on age and skin. When bone support is removed, the skin and muscle over it have less to drape on. In your twenties the tissue usually shrinks back; in your forties, with thinner skin, the lower face can look looser. If the front of your jaw and chin are also part of the plan, it helps to think of the jaw and chin as one line, as described in V line surgery for the jawline and chin.

Correcting unevenness later is possible to a degree, but only in one direction. More bone can be taken from the fuller side, while a side that went too far can only be built back with fat or an implant.

Rare risks: a broken jaw and facial nerve weakness

An unplanned fracture of the lower jaw during or after angle reduction is rare. It's more likely when the remaining bone is thin or when a cut runs further than planned, and it's usually repaired with plates and screws, with a longer recovery. This is one more reason the CT matters: bone thickness is measured before the cut instead of guessed.

Weakness of the lower lip on one side, from the small facial nerve branch that runs along the jaw edge, is also uncommon. In the 588-case review there was one case of facial weakness on one side, and it recovered fully by six months. It shows as an uneven smile, with normal feeling, which is how you tell it apart from the sensory numbness above.

When I'd tell you to wait, or not to have it

In short, these are general reasons surgeons hold off, and your own exam may add others:

• Your width is mostly the masseter muscle. When you clench and the bulk at the angle hardens and grows, removing bone won't touch the main cause.
• Your face looks uneven because of your bite or the position of your teeth. That's a question for an orthodontist and a bite specialist, and contouring the outer bone won't fix it.
• You smoke and can't stop around the surgery, take blood thinners you can't pause safely, or have a bleeding disorder.
• You're pregnant or breastfeeding, or an infection in a tooth or your gums is still active.
• You're hoping for a specific face from a photo when your nerve position or bone thickness limits how far the angle can go.

I see plastic surgery as a form of self-care, and its purpose is a happier life with your own face. If the safe version of the operation wouldn't make you happier with what you see, my answer is no, and I'll explain why.

You can read who works in the facial contouring center, and where each surgeon trained, on VG Plastic Surgery's English site.

What if something comes up after you fly home?

Put simply, this is the question under most jaw questions. Knowing what's normal and what isn't covers much of it.

Normal in the weeks after: swelling that changes from day to day but is going down overall, a stiff jaw, tingling or numbness in the lip and chin that slowly shifts, and bruising that drifts down toward the neck.

Not normal, and worth contacting a doctor the same day: swelling that suddenly grows on one side, fresh bleeding inside the mouth, fever, a foul taste or pus near the incision. Any trouble breathing or swallowing means emergency care.

Before you leave Seoul, carry your operative summary, the list of medicines you were given and a copy of your scans, and line up a doctor or dentist at home who knows you've had jaw bone surgery. How a clinic handles this part is one of the points I go through in five things a clinic list can't show about facial contouring.

When you're ready, send a front photo, a side photo taken in daylight and your travel dates on WhatsApp, with any scan you have from home, and ask how close the bone work on your jaw would come to the nerve and which records you'll carry home for your doctor there. The clinic is at 635 Nonhyeon-ro, Gangnam-gu, Seoul. At the consultation, the first thing I'll look for on your CT is where that nerve canal runs past your jaw angle.

Related pages:

• Facial Contouring surgery at VG Plastic Surgery