My poor dog is having a rough month. At some points he seems to have lost a toenail. Like the whole thing so he only has a little red nub. I'm not sure when it happened, it looks like it might have sand and stuff around it, but I didn't see any pus. He's already on antibiotics for a UTI, so should I take him to the vet about it anyway? If not, should I try to clean it or stop him from licking it?