Pimples are small red spots on the face of a person. Many adolescent boys and girls may get acne and pimples on the face during puberty due to the increased activity of sebaceous glands and sweat glands in the skin.

The excess oil secreted by sebaceous glands and sweat secreted by sweat glands get collected in the tiny pores of the skin. The accumulation of oil, sweat and dead skin cells block the tiny pores in the face skin. Then, bacteria grow in the blocked skin pores causing swelling and redness of skin which leads to the formation of pimples.