No one, not even a vet can diagnose an injury without seeing the dog !!! Get it to the vets, if you can't afford vet bills, get some insurance, if you can't afford insurance, maybe you should seriously consider not having a working dog, Sorry if this is not the advice you were after, but as long as the dogs work for us, they deserve promt, proffesional treatment when injured. I hope it's nothing to serious and the dog makes a full recovery.
Cheers.