that would probably be impossible, the other tampon wouldn't of gone in if there was one in there.
and if you did, take the one out and stick your fingers up there and see if you feel a tampon.
and if that's gross to you, and your that scared, then you should probably get over thatt fear, cuz I mean, common, it's not like your doing it for any other reason but to find out an answer to a question you have.
good luck