The Unfortunate Importance of Beauty, by Amanda Filipacchi

In this odd book, a group of people who have formed a support group called the Knights of Creation deal with beauty -- their own, their lack of it, their attraction to it -- in extreme ways.  The gorgeous Barb makes herself unappealing, the hideous Lily uses her musical gift to make herself irresistible, and others with preposterous creative gifts tug the narrative in unexpected ways.