To find out which side of the facial nerve is paralyzed, it is recommended that the patient can do a self-examination in front of a mirror, such as which side of the forehead lines have become lighter or disappeared, which side of the eyelids are not fully closed, which side of the mouth has cheek puffing and air leakage, and which side of the mouth is tilted when showing teeth. Generally, the facial nerve on the paralyzed side will show loss of frontal lines or shallowing on the same side, incomplete closure of the eyelids on the affected side, air leakage from the cheeks on the affected side, and the corner of the mouth being pulled over by the healthy side when showing the teeth.