Small raised particles on the skin may be keratosis pilaris, acne, viral warts, chestnut pimples and so on. 1. Keratosis pilaris: the cause is not very clear, may be related to genetic factors, vitamin A deficiency and other factors, may cause the skin has a raised small rash, the appearance of chicken skin-like changes, so it will lead to raised small particles on the skin. 2. Acne: It is a chronic inflammatory skin disease of the sebaceous gland unit of the hair follicle. The hair follicle is hyperkeratotic, and when sebum and other substances accumulate at the mouth of the hair follicle, pimples are formed, which may also be manifested as small raised particles on the skin. 3. Viral warts: These are benign skin lesions caused by human papilloma virus infection, such as flat warts, common warts, filiform warts, etc. They can cause raised particles on the skin. 4. Milia: These are retention cysts that originate in the epidermis or appendages and can also cause raised bumps on the skin. There may be other causes of raised bumps on the skin, so you need to go to the hospital in time and follow the doctor’s instructions for treatment.