Rebecca compulsively picks at her nails. Ian used to bite the inside of his cheeks. In this episode of GROUP, mental health counselor Merrill Black explains how compulsive self-grooming works and how to treat it. We also hear the story of a young woman with trichotillomania (compulsive hair pulling). And we chat with the founder of a mental health nonprofit about her experience with excoriation disorder (compulsive skin picking).