Menu Healthy Lifestyle Diseases & Conditions First Aid Symptoms Tests & Procedures Videos Definitions FAQs Bell's palsyUpdated: 2017-06-13OverviewBell's palsy causes sudden weakness in the muscles on 1 side of the face. It may be a reaction to a viral infection. It rarely occurs more than once.SymptomsThe affected half of the face appears to droop.TreatmentsBell's palsy usually resolves on its own within 6 months. Physical therapy can help prevent muscles from permanently contracting. © 1998-2022 Mayo Foundation for Medical Education and Research(MFMER). All rights reserved. Terms of Use