[alaskayorkie]

If he's showing any signs of discomfort, I'd worry and call an emergency vet.

If not, I would think you're OK for the night. I Googled around a bit, and most of the comments I found said it's not something you should worry about tonight. If he swallowed anything, which is unlikely, he's likely to pass it just fine. I'd keep an eye on his stool and see if he passed it.

I'd call the vet tomorrow just to be sure. I'm sure an X-ray could spot it pretty quickly. It's not something you would want staying in his system. But again, if he swallowed it it's likely to pass on its own.

Keep us informed, and good luck.