There is no way to prevent Bell's palsy.
If the symptoms are mild, treatment may not be necessary. Most commonly, people with Bell's palsy are prescribed prednisone (Deltasone, Orasone and others), a corticosteroid, to reduce the inflammation and swelling in the nerve and to decrease pain. Some doctors prescribe a combination of prednisone and an anti-herpes virus drug, such as acyclovir (Zovirax), an oral drug that attacks the herpes virus. The medication usually is taken for 10 to 14 days.
If the Bell's palsy is part of the Ramsay-Hunt syndrome, treatment with a higher dose of acyclovir is needed. Bell's palsy related to Lyme disease is treated with antibiotics active against the bacteria that cause Lyme disease.
If Bell's palsy is affecting your ability to close your eyes, your cornea can become dry and possibly get scratched. To prevent this, you must protect your eye from wind and dust by wearing glasses. You will need to keep your eyes moist by using artificial tears frequently during the day and lubricating your eye at night with a sterile eye ointment.