From the article:
It is known as Dermatophagia, and is described as a form of obsessive compulsive disorder in which a person obsessively bites or picks at their own skin. Generally it manifests itself on the person’s fingernails, but it can also occur inside the mouth, focusing on the cheeks and lips (as well as the outside of the lips), a person’s feet, or other parts of the body. Suggested “cures” for this disorder include bad-tasting deterrents (like nail polish on the nails), mouth guards, or in extreme cases, psychotherapy. Sufferers of this disorder are affectionately known as “Wolf-Biters.” I kind of like the sound of that.
Read more at Persephone Magazine.