Bell's palsy is a condition that results in the sudden onset of weakness or paralysis on one side of the face. The cranial nerve affected in Bell's palsy is cranial nerve VII, also known as the facial nerve. This nerve controls the muscles of facial expression and also plays a role in taste sensation. Damage to the facial nerve can result in symptoms such as drooping of the eyelid or mouth, difficulty closing the eye, and loss of taste sensation on the affected side of the tongue.
