According to Mayoclinic.com:
Body dysmorphic disorder is a type of chronic mental illness in which you can't stop thinking about a flaw with your appearance — a flaw that is either minor or imagined. But to you, your appearance seems so shameful that you don't want to be seen by anyone. Body dysmorphic disorder has sometimes been called "imagined ugliness." Also called dysmorphophobia, the fear of having a deformity.
I first heard and known about this serious mental illness many years ago while watching Oprah on TV. One of her guest is a women who suffers from this condition and it was already disturbing because she can't seem to be satisfied with her looks like that she underwent numerous plastic and reconstructive surgeries already. She's too obsessed on her physical appearance and she always find flaws in her herself.
BDD sufferers think that they are so ugly and look like a monster when they look themselves in the mirror. They have deep obsession about how they look. They often withdraw themselves from people but for some surgery is the only solution to make them beautiful. As a result, they become addicted to plastic surgery too. So sad to know that this condition really happens.
Some sufferers can start when they are still kids who are often told that they are not pretty or handsome and that they are worthless.