Ingrown hairs are caused because of lack of natural exfoliation in the skin. When you pull the hair out by the root a new thinner hair tries to pop out. The cells in the follicle will build up if your skin does not exfoliate itself. That creates a barrier so the new skin curls up instead of being able to poke through.
“Many African-Americans, Latinos, and people with thick or curly hair develop a type of ingrown hair called pseudofolliculitis. More commonly known as “razor bumps,” this collection of little bumps is common on the beard area after you’ve shaved, waxed, or tweezed to remove unwanted hair. Web MD