Numbness After HIFU: What's Normal, What's Not

A numb or tingly patch after HIFU (high-intensity focused ultrasound) lifting usually fades within about 4 weeks. A mouth corner, lower lip, or eyebrow that moves less on one side is a different situation. That kind of weakness typically resolves in 4 to 6 weeks too, but you should tell your provider and get examined instead of just waiting.

Why Does One Side of My Face Feel Numb After HIFU?

Why Does One Side of My Face Feel Numb After HIFU?

HIFU doesn't heat the skin surface. It focuses heat at set depths of roughly 3 to 4.5 mm, in the tissue under the skin and in the SMAS. Small nerves run near those depths. If heat or inflammation irritates one of them, it can stop working properly for a while, and you feel numbness or notice weakness. Nerve paths differ slightly from person to person, so the same treatment can affect just one side.

SMAS: a thin layer of connective tissue under the fat that covers the facial muscles. It's one of the depths HIFU targets.

Why Does One Side of My Face Feel Numb After HIFU?

Two areas are usually treated as "no-go zones" because nerves run close to the surface there: the temple and forehead, and the area just below the jawline. Below the jaw runs a nerve branch that controls the muscles pulling your lower lip and mouth corner down. If that branch is affected, one side of your lower lip or mouth corner moves less when you smile.

How Often Does It Happen?

How Often Does It Happen?

Not often. A review that pooled 16 studies and 573 patients found temporary abnormal sensation (numbness or extra sensitivity) in 4 people. In a separate chart review of 39 patients at one center, 3 had temporary lip or brow weakness. Most of those patients also had laser treatment on the neck the same day, so that group isn't a typical HIFU-only case.

Reports to the FDA's device problem database tell a slightly different story. A 2025 review of those records found that nerve damage, focal numbness, and abnormal sensation were among the most frequently reported issues. That database collects voluntary reports, so it can't tell you how common something is. It does show that nerve-related effects are the ones people notice and report.

Numbness or Weakness: How Can You Tell?

Numbness or Weakness: How Can You Tell?

A mirror and a few facial expressions usually sort it out. If the skin feels numb, pins-and-needles, or "not quite yours" when you touch it, but both sides of your face move the same, a sensory nerve is involved. If one side lags when you show your teeth, pucker your lips, or raise your eyebrows, a nerve that controls muscle movement is involved.

If it's numbness only, trace the numb area in front of a mirror with an eyeliner pencil and take a photo. Repeat it every few days the same way. You'll see right away whether the patch is shrinking. If your expression has changed, though, that's not something to track at home first. Tell your provider.

How Long Until It Wears Off?

How Long Until It Wears Off?

Muscle weakness from this kind of nerve irritation typically resolves in 4 to 6 weeks without lasting effects. In one center's look-back at 42 cases, weakness resolved in an average of about 3.2 weeks with early physical therapy, compared with about 4.6 weeks without it. The groups weren't set up in advance for comparison, so treat these as rough guides, not a promise.

How Long Until It Wears Off?

Numbness usually lasts longer than 3 days but settles within about 4 weeks. Keep in mind there's one report of stinging and abnormal sensation that lasted about 6 months. Recovery differs from person to person. If a month has passed and the numb area hasn't shrunk, it's worth getting checked again.

What's Normal, and What Needs a Call Right Away?

What's Normal, and What Needs a Call Right Away?

Soreness, tenderness when you press, swelling for a few days, and a dull feeling when you touch the area are part of recovery if they ease a little each day. Redness tends to settle in about 2 days, swelling in about 8, and bruising in about 20. If you're within those ranges and your face moves the same on both sides, it's reasonable to keep taking photos and watch.

Don't wait if you notice any of these. Contact the clinic that treated you right away:

• One side of your smile, lower lip, or eyebrow moves less than the other
• Numbness that spreads or gets worse after the first week
• Blisters, oozing, raw skin, or skin turning dark where you were treated
• Worsening pain with pus or warmth
• Eye pain, blurry vision, or trouble seeing

Muscle weakness and eye symptoms fall into the severe tier of HIFU complications, and they need prompt medical care. Even if many cases resolve on their own, don't put off the exam.

What Should You Bring When You Reach Out?

The first thing a doctor wants to know is which depths were used and where. Ask the clinic that treated you for the device name, the depths used (for example, 3.0 mm and 4.5 mm), and the number of shots per area. Take three photos in the same light: smiling with teeth, puckering your lips, and raising your eyebrows. Add a photo of the numb area traced in pencil.

If you're in Seoul and want STON Clinic to take a look, send your treatment date, the day symptoms started, and those photos with your first message. When to have HIFU again, and at what depth, is decided at an exam after your sensation and movement have fully come back.