I began wearing my TMJ splint 2 weeks ago to combat my horrific, chronic, debilitating headaches that I've suffered with for 8 years. On week 2, I began getting worse headaches and pain in my neck! Can it take a long time to calm the muscles down? I had it adjusted with very small amounts of positive change. AND, how can this work at night when my jaw automatically settles back into it's regular position and is not automatically going into the daytime position? I am desperate for relief and am losing hope....
I would call up your doctor and ask him/her some very specific questions. I'm not a doctor but intuitively I would think, if the treatment is working, that you should expect less pain rather than more pain! You might ask if it is normal to feel worse at first and, if so why? If that answer makes sense to you then ask for a time frame in which you can expect to feel better. If the doctor answers don't make sense to you then consider stopping the treatment before things get worse.
There is no certificate in TMJ treatment to earn - no AMA approved protocols. Doctors are doing treating this on their own - by necessity, for sure, but this means that there are no real standards for care and they're trying alot of different things - some of which can help and some of which can leave you in worse shape.
The TMJ Association, for instance, does not recommend 'repositioning splints'- which is nose is what it appears that you are trying. Good luck!