The recommendation was to keep it light, but every 2-3 days do a light lunge and when he's relaxed ride about 20 minutes. Trotting and cantering is okay, but keep him in a long and low type frame. No collected work. She checked my saddle again, and still thought it looked like a good fit but agreed that adding my thinline pad underneath is a good idea. She also suggested a round of acupuncture, which neither Cupid nor I have tried before.
The doc is a DVM but primarily does chiropractic work now, and has been seeing Cupid regularly (usually about every 2-4 months depending on his workload and how he looks) since I've had him. I like that she mixes both eastern and western medicines (ie. she is not afraid to prescribe muscle relaxers, in addition to the chiro and acupuncture.)
Cupid was very good standing while she applied the needles, and then about 15 minutes afterwards with the needles in. I wasn't worried about the needles specifically but he does generally get bored standing around - but he was super relaxed and happy to hang out. She put two smaller needles on each side of his neck, and about four longer ones on each side of his back. She also hit his "ting points" above his hind hooves. Although I still don't quite understand how it works, it was interesting learning a little about it and I hope it will help Cupid be more comfortable!