Acne Acne is a disease that affects the skin’s oil glands. Sebaceous glands are tiny, oil producing glands connected to hair follicles beneath the surface of the skin. The sebum moves up the hair follicle to the opening of the follicle. However, if there are dead skin cells, the sebum acts like glue and together block the pore forming a plug. Normally harmless bacteria that live on the skin can contaminate and infect the plugged follicles, causing papules, pustules, nodules or cysts. It can be painful, particularly when it’s severe. It can also cause emotional distress. Acne that appears on your face can impact your self-esteem and, over time, may cause permanent.