WATCH: The woman who lost her smile overnight

Clare Mount will always remember the evening of Christmas Day 2003 as "the night that stole my smile".

Clare suffers from Bell's palsy, a common cause of facial weakness, which occurs suddenly, and is a form of facial paralysis resulting from damage to the seventh cranial (facial) nerve.

In addition to facial paralysis, symptoms of Bell's palsy may include pain, tearing, drooling, hypersensitivity to sound in the affected ear, and impairment of taste. Twitching and weakness or paralysis of the face are the most common symptoms of this disorder.

The prognosis for Bell's palsy is generally very good. With or without treatment, most patients begin to get significantly better within two weeks, and about 80% recover completely within three months.

For some, however, the symptoms may last longer. In a few cases, the symptoms may never completely disappear.

^{Image credit: BBC News}