Comedone

A comedone is a pore blocked with a mix of sebum and dead skin cells. It is the basic lesion of acne, before any inflammation.

Open comedones are blackheads. The dark colour is not dirt — it is the blocked material oxidising on contact with air. Scrubbing harder does not remove them and washing more often does not prevent them.

Closed comedones are whiteheads: the same blockage with skin closed over it, appearing as small flesh-coloured bumps, often across the forehead or along the jaw. These are the ones people mistake for texture.

What helps: salicylic acid, because it is oil-soluble and can work inside the pore, and retinoids, because they normalise how quickly the pore lining sheds cells. Both take weeks.

What does not help: squeezing, which pushes material deeper and frequently leaves a mark that lasts far longer than the comedone would have; pore strips, which remove the top of a blackhead and nothing more; and scrubs, which irritate the surrounding skin without reaching the blockage.

A comedone that becomes red and sore has become inflamed, and that is a different problem.