I had it and recovered completely by taking homeopathic medication. I took one dose of the steroids that the emergency room physician prescribed but stopped and took only the homeopathic due to the serious side-effects associated with Prednisone.
I never really looked up the how or the why…I was too concerned about the recovery…but here is a summary:
I had it for about three weeks it was really random and the doctor said it can sometimes be caused by a viral infection. I took Prednisone (steriod tablets) six of them altogether in the morning.
To be honest don't worry about it cos it does take a bit of time but it does dissapear. If you treat Bell's palsy within 72 hours with medication it has a better effect.
Some people get it worse like when you're sleeping you have to force your eye shut. I got really dry eyes from it but just used soothing eyedrops once every hour.