There are two types of razor bumps. Transfollicular penetration and Extrafollicular penetration. Transfollicular pseudofolliculitis occurs when the hair tip is trapped under the skin below the razor bump. Extrafollicular pseudofolliculitis occurs when the shaved hair grows out of the skin, but curls back into the skin, creating a loop of hair on the skin surface and a razor bump at the point of re-entry.