Bell's palsy
Bell's palsy usually cures itself, sometimes in a few weeks. Corticosteroids (cortisone steroids) have been found to improve the condition while anti-viral drugs have not. Early treatment is necessary for steroids or drugs to be effective, but it is controversial wether or not they work.  Most people recover spontaneously and achieve near-normal to normal functions. Some people however will never regain full facial movement, or it may take a longer time. Many show signs of improvement as early as 10 days after the onset, even without treatment.