last year the horse I was leasing had a similar experience. I think he slammed his foot intot the ground when he got stung by a bee, and jumped about.
anyway, he was sort of off, then ok, then worse, and then with paddoc rest, got somewhat better, such that his owner lunged him and so on and so on. all the while we had him wrapped and did some cold hosing and all. but, the long and the short of this was that he did NOT get better, and stayed "off", and rest got him better, but if we made him move much, thinking he was better, he was worse again.
his owner felt that it was some kind of soft tissue injury, and did not want to pay for a vet , sincd the vet would say, "paddock/stall rest" and that was what she was doing anyway.
after months, she had to move him to a semi retirement situtation, so that was the end of my time with him.
so, I'd get the vet out, and I'd rest him twice as long as you think you should. that's my limited advice, based on my limited experience.