Hi thanks for query Bell s palsy is a disorder of the nerve that controls movement of the muscles in the face. This nerve is called the facial or 7th cranial nerve. Damage to this nerve causes weakness or paralysis of these muscles Bell s palsy is thought to be due to swelling (inflammation) of this nerve in the area where it travels through the bones of the skull. No treatment is needed. Corticosteroids may reduce swelling around the facial nerve .Symptoms often begin to improve right away. However, it may take weeks or even months for the muscles to get stronger, and this may be frustrating. If you did not lose all of your nerve function and symptoms began to improve within 3 weeks, you re more likely to regain all or most of the strength in your facial muscles. Response to stem cell therapy are unclear