Razor bumps, or ingrown hairs, happen after you shave, when strands of hair curl back on themselves and grow into the skin. This irritates the skin and causes pimples. Razor bumps are sometimes called razor burn.

Razor bumps form most often on the neck. But they can occur in any area that is shaved (such as the cheeks, underarms, pubic area, and legs and arms).

Razor bumps occur most often in people who have tightly curled or spiral hair strands. Using different shaving methods can help.