We have pores all over the body, but particularly on the head and neck, and the face, the nose, we have a large concentration of sebaceous glands, which are the oil-producing glands.

Blackheads also tend to tightly fill and widen oil gland ducts. Blackheads behave like bottle-cork plugs. Sebaceous filaments, on the other hand, do not have oxidation-induced darkening of the ...