My current gf is MESSED UP?

This is a bit harsh of you to do that because when she finds out she is going to be very hurt knowing it was fake. She might look the way she does but she has just as much feelings as the prettiest girl in the world. I think the longer you leave it, the worse it's going to get. Because that's like your dream girl going out with you then finding out it was a joke. I think you should just say to her that it's not working and you just want to be friends. Don't tell her about the bet, it's just a White lie, shed be hurt if you told her. And as for the money, I don't think it's worth breaking someones heart and making you feel in an akward position x