From my own experience, my PPID/severe IR mare can be footsore from an aggressive trim even when her insulin/ACTH are well-controlled. I think you need to draw blood *today* to see if the insulin & leptin are elevated, which would tell you to tighten diet/poss increase perg vs normal insulin status & hes sore just from too-aggressive trim.
IMO/E, the glucose & ACTH tests drawn *today* are likely to be higher than normal bc of pain/stress of soreness; you can always call lab to add on a glucose once you get insulin results (cannot w ACTH, however, unless vet draws the special purple top sample & overnights it & puts it on hold w lab, but u may get charged for the special handling...idk)
Furthermore, if todays insulin is high you'll likely have to increase perg (if rest of DDTE is good) and (ideally) be re-testing ACTH in 3-4 weeks for dose assessment
Please note this is from my own experience of just *one* difficult-to-manage PPID/IR case, so i defer to those much more experienced than I for advice. I just wanted to throw some ideas out there to mull over bc your vet was on his/her way....and Im also avoiding going out to mow my lawn!