Body dysmorphic disorder, or BDD, is a mental health condition where a person finds it hard to stop thinking about perceived flaws in their appearance. Intrusive thoughts make a person with BDD obsess over perceived flaws they think are obvious even if those flaws are not noticeable to others at all.
Every person has insecurities about their bodies, however, a person with BDD has an obsession with a specific aspect of their appearance they results in behavior like avoiding mirrors, not wanting to go out in public, acne, scars, wrinkles and hair loss.