A lump in armpit ingrown hair is a small, hard bump that forms under the skin of the armpit. It is caused by a hair that has grown back into the skin instead of out through the skin's surface. This can happen when hair is shaved, waxed, or plucked. Ingrown hairs can be painful, itchy, and unsightly.
Lumps in armpit ingrown hair are a common problem, especially among people who shave their armpits regularly. They are usually not serious, but they can be uncomfortable and can lead to infection if they are not treated properly. There are a number of different ways to treat ingrown hairs, including over-the-counter medications, home remedies, and professional treatments.