Hi, my son is 18 months, and he just picked up a small piece of either glass or ceramic, I m not sure which. It was a piece that chipped from a mancala stone. He chewed it and we got some out of his mouth, but I think he may have swallowed a little of it. It was almost exactly the size of a clipped fingernail, but we got a chunk out, so smaller than that... Should we take him to an emergency room, or wait it out?