Might have scratched his cornea, but I think only the vet can tell for sure. We thought this happened with our Twinkie a month or so ago, and the vet put some type of dye in her eye in order to check it. She didn't think there was anything wrong, but she had us putting in an antibiotic eye drop just in case. Hopefully he's ok. Just keep a close eye on it. Someone else may have better advice.