I don't know if I would "stress" out it if is tissue damage. Ligament and Suspensory, yes. I say this because Nelson, my 21 year old TB injured himself in his stall last January.
At the time, he was beside a pony that he didn't like, and his way of expressing his distaste for the cute little guy, was kicking at his stall wall that stood bewteen the two.
The next morning, when the Barn Help came to turn the horses out, they discovered Nelson's hind right was swollen immensely from his stifle, down to his ankle. I mean, SWOLLEN!! 3x the normal size. The barn called me at work that morning, and informed me of what they found, and I contacted my Vet asap, and she got out there to examine him.
She called me a few hours later, and told me it was severe tissue damage *at the time we had no idea he was kicking his stall, and had no idea how he managed to let that happen* and that he was on strict stall rest, and cold hosing, cold poulticing, and bute.
Eventually, after a few days of cold poulticing - 3 holes were discovered on the inside of his hind right hock, where alllll that swelling that had no where else to go, but out - was gooping through. It was a mess! My vet came back out, and changed the "attack" plan.
I sincerely thought he was done. I honestly thought he was going to be a Pasture Puff for the rest of his life, because that injury looked NASTY!
But eventually, a few months later, he was walking on his leg, he was trotting on his leg and moving like, nothing happened. My vet came out, AGAIN, and after assessing his movement and doing lameness tests, he was given the pass to be ridden again - only at the walk, and eventually the trot and etc, etc.
Through the lameness test, he showed signs of wear and tear when I trotted him off - so I made an appointment with a Equine Lameness Specialist in my area, and we hauled him over to get xrays. The vet did a full exam on him, and palpated him from his hocks, to his stifles, to his lower back and explained everything. We ended up giving him full injections in both hocks, and both stifles and he is now on a monthly dose of Adequan and we're back to our normal routines and Evented up a storm this past 2010 season and look forward to our 2011. He turns 22 in April.
The swelling in his hind right, is still there. It'll always be there. It isn't noticeable unless you walk right up to him and compare both hinds. When you do that, you can see it. My vet said that it'll always be there, because of the tissue damage, but it isn't hindering him in any way, nor does it cause him discomfort.
I put him on B-L Solution Pellets through SmartPak, and that seemed to work. The swelling actually was non existant for a while there, but due to the Devil's Claw in the product and Nelson having ulcers, I took him off of it - and the swelling came back.
So, if it is tissue damage, I don't know if that means "make or break" his riding career - but that can only deciphered by a Veterinarian who deals with Equine Lameness.
I do highly recommend you have xrays or ultrasounds done, absolutely. Figure out what exactly is going on.
I'll keep my fingers crossed for you! Keep us posted on what the results are! I know how stressful this is, been there, done that - but you're doing your best!