Well atleast you know a possiblity that its just nothing serious, and that he was just kicked. Wow May 8th is pretty much a month away If I was a vet and somebody needed to be sure there horse is OK, i'd be out there right away somehow squeezing it in my schedule.

Hopefully its nothing serious, and it'll start to go away. Or he'll be fine till the vet comes to take care of it. I hope he feels better, if it is bothering him and you can't see it is.