There may be the following reasons for acne on the neck: 1. Allergic skin disease, mainly caused by contact with allergens, can be manifested as local red papules with itching. 2、 Virus infection causes skin diseases, such as filamentous warts, flat warts, common warts, etc. If it is a child or teenager, it may also be contagious soft wart. 3、 Soft fibroma is a benign tumor of the skin, which shows soft cystic neoplasms with soft skin color and texture.