Acne on the back of the neck may be caused by endocrine imbalance, cornrows, folliculitis and so on. If you have recently stayed up late and eat a chaotic oily diet, it may cause endocrine disorders, leading to enlarged pores, increased androgens, rough skin, and the secretion of excessive oil, which is favorable to the reproduction of acne bacteria, thus appearing in the back of the neck, as well as the face or other parts of the pimples. Corns are usually associated with genetic factors as well as skin damage, and usually present as symptoms of acne on the back of the neck, mainly in the form of multiple hard white or yellow pimples. If there are pathogens infecting the hair follicles at the back of the neck, it may cause folliculitis, which manifests as red pimples on the back of the neck accompanied by white pustules at the top, and can occur on all parts of the body except the neck. If the acne on the back of the neck is serious, it is recommended to go to the hospital for examination and standardized treatment according to the doctor’s instructions.