I have a rash from a quarter.. help!?

I put two quarters in my bra, cause i didn't have pockets. I forgot about them and left them there like, overnight and when i showered the next day i had like a mark. Oh well, I figured it would go away. But now it turned into a rash, that won't go away. and i've put like calamine lotion or whatever on it but it won't go away. Help! It's been like.. 3days/