How sure are you that it's mold? Can you post a picture?
Relax, don't worry, your beer is probably fine. From my limited experience, it probably is just krausen that the yeast made since they got a jump-start, so to speak, from being transfered. Don't mess with it, just wait it out. If it goes away, you're fine. If it is mold, then there's nothing that you can do as far as I know.