Collect the evidence 
You can ask her to prove what she says beacuse this method will help you to save yourself in this senario. If she has any proof then you can admit but if she doesn’t then you are not to be counted as faulty.
Witnesses Confirmation

You can ask your friends to guide you and lead you in this senario ifthey have seen you touching her in the club . Ask for the honest opinion. If they confront this as no, then you have the strong point to say that while dancing you haven’t been close to her or never touched her then how can I do this in any room or in any state.