The redness and swelling of the half of the face is seen in the following diseases: 1. Ask the patient if there is fever, swelling and pain in the throat and teeth. If there is pain in the throat, consider if there is acute tonsillitis, or if there is swelling and pain in the angle of the jaw and swelling of the lymph nodes behind the ear, consider that the patient may have mumps. If the patient has toothache, it may also be an odontogenic infection that causes the obvious redness and swelling of the half of the face. 2. If there is herpes zoster on the head and face, the redness and pain of the half of the face is also dominant in the early stages, and then the herpes of the face appears, so the redness and swelling of the half of the face is mainly considered for the above reasons.