Bell's palsy is a temporary paralysis of the facial muscles caused by inflammation of the facial nerve, resulting in an inability to control facial expressions on one side of the face. Symptoms include drooping of the mouth, eye not closing, and loss of taste. While the cause is unknown, it is sometimes linked to viral infections. Most cases resolve on their own within a few weeks or months with treatment like antiviral drugs or corticosteroids, but rare cases may require surgery.