If you have a small rash on your face that is not painful or itchy, if it occurs during puberty, it is most often acne. Acne is caused by poor excretion of cortical or keratinous material that is retained under the skin, and is related to the exuberant secretion of sebaceous glands during puberty, and can be treated by topical application of retinoic acid cream, as well as adapalene gel and other drugs that have a dissolving effect on acne and antikeratosis. In addition to acne, it can also be a sweat duct tumor, which usually occurs on the lower eyelids and other parts of the body, and is characterized by small, painless, non-itchy, skin-colored raised papules. It may also be erythema nigricans of the face and neck, which mainly occurs on both sides of the cheeks, the patient’s skin is red, rough skin, can also be accompanied by peri-artificial keratinization of the upper arms, treatment can be applied topical emollient, moisturizing products, can also do laser relief symptoms.