Acne in the neck behind the ear. Clinically, it is seen in the following diseases: the first disease, sebaceous cyst behind the ear, is the most common clinically and is mainly found in patients who usually like to eat greasy food, are relatively fat, are severely overweight, often stay up late, get on fire, eat spicy stimuli, smoke, drink, have irregular diet, and have endocrine disorders. It is mainly due to the obstruction of sebaceous gland secretion, which leads to the repeated accumulation of secretions inside the sebaceous gland and the expansion of the cystic skin to form a retention cyst. Clinically, antibiotic ointment can be applied in the early stage, and patients are advised to eat a light diet to see if it can disappear. If it is gradually getting bigger, with local redness, swelling and pain, anti-inflammatory treatment is clinically required. Some patients, for example, continue to increase the local formation of abscesses, may need to be treated with incision and drainage. The second disease, easy to grow herpes zoster, some patients with low resistance immunity, a history of herpes in the past, easy herpes recurrence. Herpes zoster is characterized by a gradual increase in the area of pain, exudation and other changes in the acute phase, a significant painful sensation when it invades the surrounding trigeminal nerve, hearing loss when it invades the auditory nerve, vertigo when it invades the vestibular nerve, facial paralysis when it invades the facial nerve, and other related changes.