Blackheads are a type of comedo. Comedones occur when the pores in the skin become plugged with dead skin cells and an oily, protective substance known as sebum.
Blackheads don’t mean your skin is dirty. Melanin, which is what gives skin its color, is found in sebum, too. When that melanin is exposed to air (what’s called oxidation) it turns dark, and that’s what gives blackheads their typical color. So resist the impulse to scrub your skin hard to remove the “dirt,” since that’s not what’s causing
pimples, plus scrubbing can irritate skin and make acne even worse.
Blackheads are the first stage in the progression of a pimple. When too much sebum is produced and there are too many dead skin cells, microcomedones (which aren’t visible to the naked eye) are formed—setting the stage for blackheads. From there, if a blackhead isn’t treated, it can progress to a whitehead below the skin, and then on to a larger, more inflamed papule or pustule. So keeping your skin free from blackheads, as much as possible, can help your acne from getting much worse.