The common term for a small, raised, inflamed spot on the skin is a pimple. A pimple forms when a hair follicle becomes clogged with sebum, dead skin cells, and sometimes bacteria, producing a localized inflammatory bump.
Pimples are one visible feature of acne, a skin condition that often develops when oil production and follicle blockage increase during puberty. Hormones called androgens stimulate sebaceous glands, which helps explain why acne commonly begins in adolescence, although pimples can occur at any age. Whiteheads and blackheads are non-inflammatory acne lesions, while red, tender bumps are inflamed forms.
“Zit” is an informal synonym, and “blemish” is a broad cosmetic term that can describe many skin marks. “Papule” is more specific medical language for a small, solid raised lesion and is not limited to acne. Therefore, pimple is the ordinary everyday answer to this wording. Squeezing pimples can worsen inflammation and increase the risk of marks or scarring.