Bell's palsy is a type of paralysis (or weakness) of the muscles in the face, thought to be due to inflammation of the facial nerve. While it can strike anyone, Bell's palsy seems to occur more frequently in people recovering from viral infections and people with diabetes. Bell's palsy tends to come on very suddenly. You may go to bed one night with no noticeable symptoms, only to wake the next morning and find one side of your face appears to be drooping. Researchers do not know the exact cause of Bell's palsy, but viral infections, such as the herpes simplex 1 virus, are thought to be involved. Follow the links below to find WebMD's comprehensive coverage about Bell's palsy, what it looks like, how to treat it, and much more.