The difference between acne and pimples is that actually, they are of the same type. Acne is commonly known as ordinary acne, and can occur at any age stage, but is most prevalent among teenagers, hence the term "acne." It is actually a chronic inflammatory disease of the hair follicle sebaceous gland, and pimples are one type of acne. The various types of lesions in acne are caused by inflammation at different depths of the hair follicles and subsequent reactions. This includes pimples caused by blockage of the hair follicle sebaceous gland duct, as well as superficial pustular inflammation at the hair follicle opening, papules, nodules, cysts, and scars, all of which are categorized as acne. Pimples are the initial form of acne; the lesions are cone-shaped papules consistent with the hair follicles, and are divided into whiteheads and blackheads. Whiteheads are also known as closed comedones, while blackheads are called open comedones. Inside whiteheads, there is a yellow-white tofu dregs-like substance, while blackheads are oxidized whiteheads that have been exposed over time.