Acne is a great concern for many friends, especially teenagers, who are more concerned about their appearance at this stage. Most of the acne is a normal phenomenon, especially after entering puberty, due to the changes in the level of some hormones in the body, a transient acne will occur, and there is no need to worry too much. For girls, if the menstrual cycle is normal and there is no sign of hirsuteness, it may be a normal puberty reaction. Some acne may be a manifestation of disease, such as with the growth of hair in other parts of the body, especially in places where hair should not grow, such as around the breasts or below the navel hair, or menstrual cycle disorders, accompanied by changes in body shape, the appearance of purple lines on the abdomen, etc., it is recommended to go to the hospital in a timely manner for the appropriate examination to rule out specific diseases.