Guinea pig ate a little bit of felt?

I just recently got a guinea pig and I made a tunnel made of felt fir him and I was going to take it out when i got a new one. Today, he wasn't eating as much as before and he left some of his pellets. I thought it was just not hungry today. I looked in his tunnel to check if he pooped in there and found that he nibbled a part off. The felt he ate was almost the size of an eraser in length but a little smaller. Is he going to be ok or do i have to take him to the vet?