What are blackheads? What is whitehead acne? Blackheads are the most common manifestation of acne. They are usually pinhead-sized pimples with dilated central pores and lipid plugs in the pores that turn black at the top due to lipid oxidation, with white translucent plugs. This condition can be squeezed out with a pimple needle and generally does not cause other changes. Whitehead acne is usually a swollen follicular funnel with a hard-to-see opening, which appears as a pinhead-sized white or light red papule. This condition should never be squeezed, as squeezing can cause inflammatory material to enter deeper into the follicle and further develop into folliculitis, pustules, nodules, cysts, etc.