3 Answers

The most common cause of Bell's palsy appears to be the herpes simplex virus, which also causes cold sores and genital herpes. Other viruses that have been linked to Bell's palsy include:

    * The virus that causes chickenpox and shingles (herpes zoster)
    * The virus that causes mononucleosis (Epstein-Barr)
    * Another virus in the same family (cytomegalovirus)

With Bell's palsy, the nerve that controls your facial muscles, which passes through a narrow corridor of bone on its way to your face, becomes inflamed and swollen — usually from a viral infection. Besides facial muscles, the nerve affects tears, saliva, taste and a small bone in the middle of your ear. http://www.bing.com/health/article/mayo-125420/Bells-palsy?q=bell%27s+palsy

The casue of Bell's palsy is not clear.  Many cases are thoguht to be caused by the herpes virus that causes cold sores.

Infection of the brain. I had a terrible ear infection, I ended up with bell palsy. I researched the dickens My face is okay now, unless I'm tired or stressed out it happens again. Only for a day, short term.