What is facial paralysis?

Every movement your face makes — smiling, raising an eyebrow, blinking, pressing your lips together — is driven by the facial nerve. Facial paralysis happens when that nerve is damaged, inflamed, or stops working properly, so the muscles it controls stop responding.

It usually affects one side of the face, and the impact goes beyond expression: blinking, keeping the eye moist, eating, drinking, and speaking clearly can all be affected. Severity ranges from mild weakness to no movement at all — and neither says anything about the person’s mind, mood, or abilities.

Common signs include drooping on one side of the face, an eye that won’t fully close, drooling or difficulty keeping food and drink in, changes in taste, sounds feeling uncomfortably loud on one side, and speech that takes more effort.

Symptoms can appear suddenly — often overnight — or build over a few days, depending on the cause. One important exception: if facial weakness comes with arm or leg weakness, slurred speech, severe headache, or confusion, treat it as an emergency and call for help immediately. Those are stroke signs, not typical facial paralysis.

A doctor will usually watch your face move — smiling, raising eyebrows, squeezing your eyes shut — and check sensation and reflexes. The pattern of what moves and what doesn’t tells them a lot about where the problem is.

Depending on your story, they may add blood tests, imaging like an MRI or CT scan, or nerve tests that measure how well the signal is getting through. Which tests you need depends entirely on your symptoms and history — many people need only a careful exam.