An ingrown hair on armpit is a condition in which a hair grows back into the skin instead of out of it. This can happen after shaving, tweezing, or waxing. The result is often a small, red bump that can be painful or itchy.
Ingrown hairs are a common problem, especially in areas where hair is thick and coarse, such as the underarms. They can be unsightly and uncomfortable, and they can also lead to infection.