A swollen bag on the neck may be related to boils, sebaceous cysts, lipomas and so on. 1. Boil: It is an acute purulent reaction of the hair follicle and its surrounding tissues, which is often manifested as a red bag centered on the hair follicle, accompanied by pain and other symptoms. 2. Sebaceous cysts: may be due to the neck skin secretion of oil exuberance and other sebaceous gland duct obstruction, gland content accumulation and the formation of cysts. 3. Lipoma: It may be related to genetic and fat metabolism abnormality etc. It is usually a painless lump with small size, which shows the condition of a swollen bag on the neck. Swelling on the neck can also be seen in other causes, it is recommended to consult a doctor in a timely manner, follow the doctor’s instructions to carry out relevant examinations, with the help of the doctor to clarify the cause, and targeted treatment or treatment.