It is possible that the swelling behind the ear is a lymph node, because when a patient has a parotid infection or a dental infection, especially a wisdom tooth infection, it can lead to an enlarged lymph node behind the ear, which can usually be clarified by going to the hospital for a physical examination and ultrasound. Most of the swollen lymph nodes can be relieved by taking warm water by mouth and some antibiotics by mouth, and the primary disease must be treated actively to cure it. This is an infectious disease, with localized swelling and sometimes combined with skin redness, swelling and ulceration. There is also the possibility of fibroids behind the ear, which is also a benign swelling, and there is usually no need to worry too much. There is also the possibility of a lipoma, which is also not a cause for concern and can be observed, but if it grows larger, it will need to be removed surgically.