Most hair shafts will grow up through the skin without causing any problems. Other hairs may grow underneath the skin. When you shave, the shortened hair can curl back and grow into your skin. When hair grows back into the skin, the body responds to the hair as if it were a foreign object, causing inflammation. Certain people may be at a higher risk of ingrown hairs. For example, people with thick, curly hair tend to develop ingrown hairs more often than people with fine, thin hair. This is especially true with pubic hair, which tends to be coarser than the hair on the head or the rest of the body.