There are no "rules" that prevent you from doing this. So you could theoretically rematch into a PGY-1. But many programs will be uncomfortable doing so. It's somewhat a waste, since if you completed a PGY-1 already there's no need to repeat it. Also, it creates a funding issue later in your training (although the overall effect of this is small and potentially nothing -- it's a complicated situation and there are other threads that discuss it). My own personal experience with this is having someone complete a surgical PGY-1 and then want to come to medicine, then they need to repeat a PGY-1 because the surgical prelim won't get them credit. It can be a long, miserable year -- the things that are "fun" and "challenging" the first time in your PGY-1 become painful and monotonous the second.
If you've completed a PGY-1, you can often find a PGY-2 spot in IM. It takes some hunting around.