Hi, welcome to the TN section, am sorry you've had to post here though.
Unfortunately, in a lot of cases it's almost considered 'normal' to have to go through the channels of misdiagnosis and numerous visits to the dentist, many of us started out the same as you
At least you finally reached the right person who diagnosed your condition, and it seems that you've had good advice.
I don't know much about Cerebral Venous Sinus Thrombosis, neither do I have experience in taking Trileptal, but I would hazard a guess that maybe your have got used to your dose and need to consult your doctor again to see if it is safe for you to increase it?
Did you see a Neurologist when you had the results of your scan at all?
I'm assuming that your MRI did not show any kind of nerve compression which is a bona fide TN sign (although they don't always show up on the scan).
The nerve relaxant that I have to take is Tegretol (Carbamezapine), and often in large doses as well.
Ask questions and I'll try to help you all that I can, as will many others here.