Bumps on the forehead may be caused by acne, flat warts and folliculitis. 1. Acne: During puberty, acne may be high in the forehead area due to higher levels of androgen, more vigorous sebum secretion, over-keratinization of follicular openings, and Propionibacterium acnes infection. 2. Flat warts: Mostly found on the face, limbs and other parts exposed to the outside world, they are round or oval protruding from the skin, similar to the shape of a pimple. 3. Folliculitis: Inflammation of the hair follicles due to fungal or bacterial infections can also manifest as pimples on the brain. There may be other reasons for goose bumps, we recommend that patients go to the regular hospital in time to clarify the cause of the disease, under the guidance of the doctor for standardized treatment, so as not to delay the condition.