A dermatologist is a medical doctor, earning an MD (Doctor of Medicine) or a DO (Doctor of Osteopathic Medicine) license that allows the individual to specialize in treating many of the physical featuresthat make you human. Acne is the most common skin disease in the world — 80 percent of all people experience an acne breakout at some point in their lives, often during the teenage years. Acne is a skin condition in which the pores become clogged with sebum (oil) and dead skin cells. These clogs are referred to as comedones or blackheads and whiteheads.