Sebaceous cyst with infection, congenital preauricular fistula infection, boils in the external auditory canal and so on. 1. Sebaceous cysts with infection: Sebaceous cysts can show up as a swelling in the skin, grow in the ear opening and become infected, there can be a bag that hurts when pressed, and there is usually redness and swelling. 2. Congenital preauricular fistula infection: congenital preauricular fistula infection, there will be a bag near the mouth of the ear when pressed on the pain, usually there will also be redness and swelling. 3. Boils on the external auditory canal: boils on the external auditory canal can also lead to a bag growing on the mouth of the ear that hurts when pressed, and there will be obvious pain, and there will even be the phenomenon of pus coming out of the rupture. It is recommended to go to the hospital for a complete examination and take standardized treatment under the guidance of the doctor.