It is very hard to the touch, not hot. No indications of swelling on or around it. Jake trots sound, and is fine after working. Jake has his share of scar tissue and lumps on his legs from injuries and a popped splint. But this is in an area that I haven't seen on other horses before. There is no puncture or known injury to happen to the area. Jake is older and doesn't move much in his 24x24 pen, so random kicking/playing around injuries are out of the question. He does fool around in the turn-out but nothing has happen, no signs of lameness has come up.
I've kept him in work as it doesn't seem to bother him in the least, and no new behaviors have come up and other horse people can't notice any lameness even when I'm riding. I've been keeping his riding lighter, no jumping or hard work outs, but he doesn't seem to be bothered. I've contemplated to stop riding for a while and did give him a week off when I noticed it even though he was sound.
He got shod about 4 weeks ago, and I was a bit unhappy about the shoeing. I later found out the apprentice had done the shoeing and had been having trouble with Jake laying down. I believe on this hoof the shoe is slightly off center. I don't know if that's a factor or not. I'll see if I can get better shoe shots later. But here are the shots, taken with my iphone so not the best quality.