Ingrown hairs most often occur in areas where your hair has been shaved or waxed.
These types of depilation can cause your hair follicles to break and become clogged with dead skin cells, forcing the hair inside it to grow sideways. Ingrown hairs occur particularly in the bikini line and legs for women, and in the beard and neck for men. In these places, the hair that grows back has a sharper edge and can easily poke back into the skin.
Usually, you notice you have ingrown hair when you see a red bump on your skin. If infected, you may also see pus and the bump may grow larger. The area around the ingrown hair may also appear red and irritated, swell, itch or feel warm to touch.