I had TN for about 2 years, started Carbamazepine( Brand name is Tegretol) went into remission for more than a year. TN came back and got worse and worse, added Excarbazepine in addition to Tegretol, helped for about 6 mos. Then I reached to a point I couldn't do any thing with my life. I was so depressed. Decide to seek more treatment. Had MVD at UCSD in January of 2013 (8yrs after my TN started). The Pain didn't go away or changed after the surgery even my doctor said I had 90% chance to get rid of the pain. The doctor added Phenyton (dilantin) to my drug list. I felt overdose for a few weeks but the pain was under controlled. after a few months feeling well, I started to reduce the medicine slowly (every few weeks). If I felt pain, I increased the medicine back . Today I am at 8.5 mos after my MVD. I only have to take medicine twice a day instead of 5x. My dosage is cut down 50% and I hardly feel any pain, just a little tingling sometimes (once a day)
So for my case it took more than 6 months to see the result from my MVD. Keep praying. I prayed and never gave up asking for help from God.