A comedo is a clogged hair follicle (pore) in the skin. Keratin (skin debris) combines with oil to block the follicle. A comedo can be open (blackhead) or closed by skin (whitehead), and occur with or without acne. The word comedo comes from Latin to suggest the worm-like look of a blackhead that has been secreted.
The best way to treat blackheads is to use all natural skin care treatment.