Hairs normally grow straight out of a tube in the center of a hair follicle.
Instead, it curls into the side wall of the hair follicle. These lesions are usually tender. As the hair continues to grow above the opening of the follicle, it can pull the hair tip out of, or keep the hair tip from growing into the side of the follicle. Alternatively, the hair tip may continue to grow into the adjacent skin outside of the follicle and produce a large and probably more inflamed area.