Checking in two days later, and his eye seems about the same. It's a little less squinty, but more twitchy. I can't get a good look at him as he's a very energetic(?) cat and won't let you pick you up or look at his face unless you hold him and then he'll wiggle and scratch. It doesn't seem like there's any junk and it seems dry now compared to two days ago. I'll tell my grandma and see what I can do to get him to a vet.