1. This is a manifestation of folliculitis. It is mainly due to the slow metabolism, which makes the cuticle thicker. The hair cannot penetrate the epidermis during the growth process, and pimples form over time.
2 This is caused by human factors: hair removal, shaving, shaving, etc. During the operation, the intensity changes the growth direction of the hair, and over time, pimples will form.
p>3. This is caused by genetic factors: inherited from parents, which is what we call congenital