Very lame Duke

Poor Duke was very, very lame tonight.  He had a head bob at the trot going to the right (easy to see), but then when he went left, he was like whole body heaving lame - impossible not to see.  His whole head and neck were going up and down.
I could not find any swelling, any heat, or any pressure points.  I pressed with the curry for a sore muscle in his back, and found nothing.  Both hind ankles felt a little thick but normal thick and cool.
So I gave him a gram of bute and sore-no-more on all four legs, hocks, and stifles.

He hasn't felt lame, but he hasn't felt himself for at least a week (I need to check calendar) but certainly at the derby he didn't feel like he was pushing through from behind.

So I guess the good news is if I think he feels a little off, he and I are communicating well.
The bad news is I don't know what we could have done - he wasn't off.  I guess give him a few days of stall rest and bute as soon as he feels a little off?  This will make me neurotic.

John saw him Wed and he wasn't visibly off (and didn't feel off).  Although I'd say the few rides before John, he felt a little, I don't know sluggish - and then worked out of it.

Unfortunately, he had Thursday and Friday off because I was working insane hours, so I don't know if he got worse after the jump lesson, or if it was the days off, or totally unrelated.

It is also 3 1/2 months since his steroid injection, so I guess it could have worn off (too quickly) and if he isn't better in a couple days, he'll go down to Dr. R the next week.