Special issuance Medical  

First of all, every medical issue that requires a SI has its own timeline. I had an issue 15 years ago. It took me 3 months of testing and paperwork to get it resolved, and I did not require an SI. I sought out a senior AME that was experienced in the paperwork requirement that OKLA wanted. Do as much work and research as you can, don't depend on others that you have to pay. Also, unfortunately, you are at the mercy of a lack of FAA folks reviewing paperwork, so your wait may be months. Hopefully not. Good luck and I wish you well.