This is often due to the following reasons: First, long periods of time without cleaning can lead to blockage of skin follicles. When the oil and shed dander cannot be discharged outward, it will cause infection. Second, wearing a mask for a long time will cause the skin behind the ear to rub repeatedly, which can easily lead to sebaceous cysts, and when the cysts become infected, they can become pus-filled and break down. This needs to go to the hospital and be treated by removal. Thirdly, it is caused by eating too spicy food for a long time, or drinking alcohol. It is necessary to adjust the diet structure, such as abstaining from pepper and alcohol. At the same time, the appropriate intake of vitamin and fiber-rich foods, such as fruits and green vegetables, etc.. Fourth, parotid abscess fistula, which can also occur when the parotid gland becomes infected and breaks down into the skin. Fifth, lymphatic nodules break down. In short, if an abscess persists, it needs to be seen and treated in a timely manner.