Not always hard to fix this:
If the end result is tight jaw muscles (they act more like tendons), you can release them faster by the means of trigger point release - a special 10-20 seconds of applied pressure by thumbs or fingers. I had to do this, and fended it off from getting worse. You tube probably has this.
A massage therapist who knows trigger point release can help, but you might be better off if you can find a chiropractor type of person (not all are qwakes, and not all crack you) who also does trigger point release. Its not rocket science, and it work, yet its so "foreign" to many people, and many are afraid to try it.
Active release technique
www.activerelease.com/ could also help you release your jaw in only several visits.
Massaging your jaw with deep pressure is just as important as stretching other muscles. Just
opening your jaw does not stretch the muscles there.
Obviously you need to stop what is causing this, which might take a long time, anything lyme related takes a long time IMO. The info provided above could reverse this in a couple visits. After that, you do it yourself as needed.
The medical community knows nothing about
this, since its not a drug.