Pimples
Almost all teens get acne. It happens when an oily substance called sebum clogs pores.

Pimples usually pop up on the face, neck, back, chest, and shoulders. Acne isn't a serious health risk, though severe acne can cause permanent scars. Acne can also damage self-esteem.

Acne can appear as one of the following:
#Whiteheads: White dots that are pores impacted with oil and skin covered by skin layers.
#Blackheads: Black bumps that are impacted pores in which material pushes out through the follicles. The black color is not from dirt. It may be from bacteria, dead skin cells, and matter that react with oxygen.
#Papules, pustules or nodules: More serious lesions appearing red and swollen due to inflammation or infection of the tissue around the clogged follicles, which are often painful and feel hard.
The exact cause of acne is not known, but hormones called androgens can play a role. Androgens increase in both boys and girls during puberty. Androgens make the skin's oil glands get larger and make more sebum. Androgens also can increase because of hormonal changes related to pregnancy or starting or stopping birth control pills.

Genetics may also matter. If your parents had acne, you may have inherited that tendency.
Some medications (for example, androgens taken as medicine, epilepsy medication, lithium, and prednisone) can cause acne.
Cosmetics that have a greasy consistency may also clog pores. Water-based products are less likely to cause acne than oil-based makeup. Other things that can make acne worse include:

Friction caused by leaning on or rubbing the skin; harsh scrubbing

Picking or squeezing blemishes

Pressure from bike helmets, backpacks, or tight collars

Changing hormone levels in adolescent girls and adult women two to seven days before the start of the menstrual period

Stress

Dermatologists often treat acne, particularly in severe cases. Family or general practitioners, pediatricians, or internists can treat milder forms of acne.