An ingrown hair irritates the skin. It produces a raised, red bump (or group of bumps) that looks like a little pimple. Sometimes an ingrown hair can form a painful, boil-like sore. You may notice pus inside the bumps. Or you may see the hair that's causing the problem. In men, ingrown hairs often pop up as a bunch of little bumps on the chin, cheeks, or neck after shaving. In women, ingrown hairs are common on the legs, as well as in the pubic area and armpits. You can also get ingrown hairs on your buttocks.