Have checked if he has got something stuck in his paw like a small piece of glass or a stone if not it could be very painful if you don't check his nails. Or if you can't find anything TAKE HIM TO A VET. Hope he gets better.
I like horses especially the appaloosa because they are very pretty and very stable mannered also i love my 2 dogs which are a Dalmation and a Rottweiler because they were both very easy to house train them and they are very good at agility classes.
I think that you need to try and calm down your dogs nerves he might just be a bit shocked. If he is still like thins tomorrow I would take him back to the vet. Hope your dog gets better.