Ringbone, again :(

After today's ride, I'm convinced Gali's "lameness" is indeed a flare-up of his ringbone, and no longer attribute it to time spent indoors, or a break from supplements.  He's been out for a week, and back on his supplements for longer than that - so if that's what it was, he should be sound again.  Pony's sound at the canter and walk, but grade 2/3 lame at the trot.  It's more prominent going towards the right, and nearly gone traveling towards the left, as well as when he sits down and uses his hind end to carry himself.  I do believe that getting on him and helping him stretch out is helping, so I will continue to ride (at a walk with some stretchy trot) and see if he continues to improve. I'm having his (new!) vet out to give him a botulism vacc sometime in the next week or two, so I'll speak to him then about my options.