After 48 hours of bute and two applications of liniment, Tristan's weird stomach swelling is down significantly. Not gone yet - at least not when I checked right before I left for Maine - but way better. Whew.
I didn't have time to put him on the longe but I am not as worried - he can have a few more days to rest and I will check him on Friday when I get back.
In the meantime, wtf, Wednesday night?! Uggggghhh.