It would be a little weird depending on your relationship.

If you guys are more than acquaitances, then go for it. If not, it seems a little creepy. Try IMing her instead or find something in common to talk about ie. if you have the same classes, what was the HW or if you guys have a friend in common talk about them (but not out of the blue and not spitefully) and let the conversation go from there.

She may be seriously not interested in a relationship, if so give her a little space.

Or it could have been just bs to get rid of the other guy.

Either way, you'll probably have to watch her reaction when you get back.