Bell's palsy is characterized by sudden, unilateral facial paralysis that develops over 48 hours. Early symptoms include weakness of facial muscles, poor eyelid closure, ear pain, taste alterations, and numbness of the cheek or mouth. Diagnosis is based on the clinical history and physical exam findings of unilateral facial paralysis without signs of central nervous system, ear, or brainstem involvement. Treatment involves a 5-day course of high-dose corticosteroids if started within 72 hours, along with eye protection and antiviral medication to prevent secondary infection.