One of the most common blemish-causing conditions is acne. This can cause both raised pustules and pimples as well as flat blackheads and whiteheads. These happen when a hair follicle gets clogged with a naturally-produced oily substance called sebum, dirt, or bacteria, and can also be caused by ingrown hairs. Most people have acne during puberty, when hormonal changes cause the body to produce too much sebum, which increases the changes of clogs. Over-the-counter (OTC) cleansers and medications can reduce sebum, soothe inflammation, and clean out pores for people with mild or moderate acne, but those with severe acne may need prescription anti-inflammatory and medications to regulate hormonal changes.