Kimberly Bowness started using tanning beds because she wanted to get rid of tan lines before junior prom. 

"Looking back, it all seems so silly now," she says. 

Bowness, 28, a women's health nurse practitioner in Dallas, used tanning beds three times a week for more than a month to erase the tan lines she got from playing tennis. Years later, Kimberly learned the steep price of her quest for the...