My case sounds a bit similar to yours...

I had my first TN attack 7 years ago, when I was 30. I was convinced it was dental and after four months of severe pain I was diagnosed with TN. I was put on Amitriptyline and stayed on it for two years until I wanted to get pregnant. I went off of it and the pain never came back...
Until this year. Now I am trying Amitriptyline again and it seems to be working. I am still in the process of increasing it.

TN is a progressive disease so it does not just go away. It does go into remission though. My mother has it as well and she has long periods of remission. It seems that when it does come back it gets worse, which is what I am experiencing now.

There are also different types of TN. I was quite confused because my TN does not come in short bursts of excruciating electric-like shocks. Mine always come on slowly early in the day and by the end of the day my entire left side is killing me, like I got punched in the face. It starts in my bottom and top molars and radiates to my jaw, cheek and ear all on the left side. Once I discovered Atypical TN I was like that's me!!! So everyone is different and everyone's pain is different.

And for me there wasn't a definitive diagnosis. First a dental cause was ruled out by several dentists. Next I went to a TMJ specialist who said I have TMD and was given a night guard. My MRI was completely fine. No amount of pain medication would touch it though. Amitriptyline has worked for me but it doesn't seem to be a common medication for TN and I do not think it works all of the time. These are some of the reasons this disease is difficult to pinpoint though. It just seems to be more of a process of elimination.

Good luck to you