Seven years ago, Carmen Tarleton received a face transplant, a decision she made after her estranged husband attacked her in 2007 with a bottle of lye, disfiguring her face beyond recognition. The transplant was a grueling, complex, surgical procedure -- one that ultimately proved unsuccessful. But last month, Tarleton, a 52-year-old former nurse, chose to do it again, making her the first American and only the second person ever to undergo the procedure twice.