It is not a disease in itself. The disorder may be caused by many different conditions, including Bell’s palsy, herpes zoster oticus (“shingles” of the facial nerve), injuries to the facial nerve, tumours of the acoustic nerve or of the facial nerve itself, post-operative facial nerve weakness, mastoid infection, hemifacial spasm, and stroke. 

An extensive evaluation may be necessary to determine the cause of the disorder and localize the area of nerve involvement. Diagnostic evaluation of facial nerve disorders may include hearing tests, X-rays, tear test, ENG (electronystagmography), nerve excitability test, electroneuronography and electromyography. 

The most serious complication that may develop as the result of total facial nerve paralysis is damage to the cornea of the eye due to exposure and dryness. It is most important that the eye on the involved side be protected from this complication. Glasses should be worn whenever you are outside. This will help prevent particles of dust from becoming lodged in the eye. If the eye is dry, you may be advised to use artificial tears. An ointment may be prescribed for use at night-time. In some cases of long-standing paralysis, it may be necessary to insert a gold weight into the eyelid or perform some other procedure to help the eyelid close. 

Medical treatment may be instituted to decrease the swelling of the facial nerve in some conditions. This treatment may be continued until the nerve shows signs of recovery. Surgical procedures include decompression of the facial nerve, facial nerve graft, and facial reanimation surgery. In some patients with stable partial facial movement, it is possible to improve their function with facial retraining.