Facial paralysis is a symptom caused by facial nerve palsy, typically not accompanied by pain on one side of the face. In severe cases, it may lead to distortion of the mouth and eyes, rather than just a crooked mouth. It is recommended to consult a neurology department in the hospital for a professional diagnosis to determine if the issue is related to the facial nerve. Possible causes include inflammation of the brainstem, vascular diseases, inflammation, or tumors. These symptoms should not be ignored.