If the patient’s ear swells up behind the ear, the following aspects are mainly considered. 1. There are many lymph nodes distributed behind the patient’s ear. When the patient has inflammation inside the ear or gets anxious and inflamed, the lymph nodes behind the ear may swell significantly and the patient will be more painful. 2. If the sebaceous glands behind the ear become blocked, the sebaceous glands behind the ear will locally bulge or even break down and flow pus, which is generally more common in young people. 3. Boil formation caused by bacterial infection behind the ear. Regardless of which of the above causes is triggered, it is important to actively treat the symptoms so that the swelling behind the ear of the patient will improve significantly, and if necessary, consider going to the hospital for further consultation to avoid delaying the patient’s condition.