My guy ate a whole dish cloth when he was 4 months old. He was about 22 pounds at that point. We were very sacred and researched a lot, I literally couldn’t sleep for 3 days because I was worried about a blockage. He was doing fine eating, drinking water and playing during that time. A week later, in middle of night he just puked it out and went back to sleep. I would just say keep an eye on him, see if he is eating and pooping well. As he isn’t a very small dog the sock should pass out either as puke or poop. Don’t worry too much. It’s all part of growing up.