You did all you could do so relax take a deep breath and relax. If it was a bigger dog and it wasn't limping, you can be pretty sure that it isn't seriously injured. If your bumper hit it's hip then I doubt there would be any internal bleeding and doesn't sound like you were going fast enough to do damage anyway. Bigger dogs are definitely more hardy than small ones and if the hipwas hurt, he probably would have been limping. The owner should have had them on a leash or at the very least, been keeping a close eye on them
