Dear,
Everyone heals at a different rate, and too, it depenRAB on how long you had already suffered with the disc crushing a nerve and how extreme the pressure was. So many things can affect the injury and thus the recovery.
You mention you have a scar tissue problem. I hope you knew this ahead of time and insisted that the surgeon use Adcon-L or one of the other anti-scarring gels to inhibit internal scar tissue growth. Most good surgeon will ask in advance if you have a scarring problem.
At four months, with a three level fusion, I was flying high, but to repeat again from other posts, I have a fantastic spine specialist. If you continue having problems, might it not be worth your while to search for one (if yours is not a spine specialist) or another one (if yours is) in your area and seek another opinion? Nothing wrong with you taking positive action to find out why you are not better, especially if your doctor isn't reacting to your concerns.
Hope you see noticeable improvement soon. If not, get that other opinion. Either way, let us know how you are doing.
Best wishes.