Also called: idiopathic facial paralysis Sudden weakness in the muscles on one half of the face. Bell's palsy may be a reaction to a viral infection. It rarely occurs more than once. Requires a medical diagnosis Bell's palsy is characterised by muscle weakness that causes one half of the face to droop. People may experience: Pain areas: in the ear Sensory: abnormality of taste or sensitivity to sound Also common: drooling, dry eyes, or facial muscle weakness