Can a tampon break your cherry?

Yes. Your hymen may be inured by a tampon but that doesn't mean you lost your virginity. You lose your virginity when you first have intercourse. Discuss your gynecological anatomy and health with your doctor or gynecologist.
Only in some women. Your "cherry" is called a hymen, and is a thin membrane at the vagina's opening. The hymen has a hole in the middle that should fit a tampon, but if the tampon is wider than the hymen hole, then the hymen may partly break while being stretched. There is absolutely no problem associated with having a broken hymen (cherry), and tampons are safe to use if they are changed every 8 hours or sooner.