I would venture to say that she's just trying to ignore what happened and keep things as they were. To be honest, from what I've heard it's entirely possibly that she's not really being flirty with you. It's fairly common to smile at friends, and some girls just naturally tend to touch people during interactions.

If I were you, I would just try to do whatever it is that you need to in order to forget this crush. I know you feel like there's no sense of closure, but honestly the fact that she's trying to act like it didn't happen is a good sign. It means that she wants to be friends, and I would try and go with that.