Aspirin is the one you want to give, not Tylenol. Buffered or "coated" if you have it. Poor Buddy!!! Keep him quiet and give him one aspirin. Hopefully it's "just" a pull or sprain. If he's still having a lot of trouble weight bearing in a few hours, I'd call the vet; it might be a good idea to get it xrayed. Actually, you might want to call now, since it's late on a Saturday afternoon and you might not be able to reach your vet tonight. I feel awful for you and your precious Buddy Please let us know how he's doing later this evening, ok? HUGS to you dear Buddy. Sandra