When whiteheads are exposed to air they form blackheads. Also, the mixture of oil and cells helps the bacteria, especially P. Acnes, to grow and become virulent. The increased pressure within the clogged follicle causes the wall of the follicle to rupture. As a result, sebum, bacteria and shed skin cells escape into the surrounding tissue, forming papules, pustules and nodules that can be large and painful. This usually heals within 8 weeks.
Nodular acne can result in permanent scarring.
Acne consists of whiteheads, blackheads, pimples, and sometimes, deeper boil-like lesions called nodules. Acne can be mild, moderate or severe. Mild acne can appear as whiteheads and blackheads or even pimples. If you have moderate acne, you will see more pimples and pustules on your face, and possibly on your chest or back. In severe acne, you will see a lot of nodules, which are painful and large, on your face, chest, back and maybe on other areas of your body, too.