My dog did the same thing. You should have made him throw up immediately, but by now it might be stuck in the digestive system. :( This also depends on how big your dog is. If it is a little dog, take it the to vet immediately. I had my dog swallow a sock without me knowing- and he is a medium sized dog- and he passed it okay. If your dog is showing any signs of discomfort take him to the vet. Check all of its poops to see if it is in there. Good luck!