Acne, folliculitis, and eczema may be the cause of this condition, and general treatment and medication are recommended to improve the condition. 1. Acne: A lot of small pimples behind the ears may be caused by acne, and patients need to pay attention to personal hygiene first. Secondly, Vitamin A drugs are effective in treating acne, and can be used topically with Adapalene, Tazarotene and other gels as prescribed by the doctor to promote recovery. 2. Folliculitis: Folliculitis may trigger a lot of small particles of acne behind the ear, patients should pay attention to local cleanliness, avoid pressing, scratching the affected area. It is recommended to use antibiotic drugs under the guidance of the doctor, with antibacterial and bactericidal effect, common drugs are mupirocin, fusidic acid and other ointments. 3. Eczema: Eczema may lead to a lot of small particles behind the ear pimples, patients should find out the cause of the disease as far as possible to avoid recurrence. Glucocorticoid drugs have anti-inflammatory, anti-allergic effect, can help to improve the symptoms of skin lesions, patients can follow the doctor’s instructions for topical use of Hasinide, Trimethoprim and other ointments. There are many reasons why there are a lot of small particles of acne behind the ear, and it is recommended that patients go to a regular hospital for relevant examinations, to clarify the causes, and cooperate with the doctor for standardized treatment.