Small bumps on the skin that don’t hurt or itch can be caused by keratosis pilaris, filiform warts, and milia. 1. Keratosis pilaris: the cause of this disease is not yet clear, may be genetic, vitamin deficiency and endocrine factors, the patient’s skin will appear normal skin color, light red pimples, most of the chicken skin-like, with a rough feeling. 2. Filiform warts: the cause of this disease is considered to be related to human papillomavirus (HPV) infection, mainly manifested as wart-like superfluous organisms above the skin surface. 3. Corns: These are hard, yellowish-white pimples that can be caused by heredity, skin damage and other factors. If you suffer from milia, you will have small bumps on the skin of your face. There are many reasons why small bumps on the skin are painless and itchy, so it is recommended that patients seek medical examination to clarify the cause of the disease.