Sigh, what is wrong with you people? Unless she's had healing powers since birth, her hymen wouldn't rip and heal every time because most likely it had already been ripped during the onset of menustration, inserting a tampon, or pretty much any rough activity (soccer, gymnastics, a bumpy road, etc) prior to her healing abilities asserting themselves.
A broken hymen is not an indication of virginity anyway. That's why so many medieval and renaissance parents splashed animal blood on the wedding night sheets to hang outside as a display of their daughter's purity. They just thought the girl was a slut. Whether or not she was, they didn't know any better. Modern science does. In fact, it's known this since at least the 40's, if not longer.
I know there's a loser who's hot on the girl from Heroes for this same reason, but all the masturbating to cheerleaders in the world won't make it true.