I don't know where you live, but you might want to check out I-therm; kldmedical.net/i-therm. There's a video on youtube showing a treatment, too. I have experience with acupuncture, chiro and I-therm and would highly recommend I-therm for the issue that your sweet boy is having. It's an amazing piece of equipment that is used for people and animals - OSU Vet School has one. To save time, I would call the manufacturer and see if they can point you toward the closest Vet to you that has one.
Sending prayers of comfort and healing white light to Clever.