Hi,
As Valkyrie says everone's experience of TN is different just as where you live can impact on how it is managed.
In the research I've done there are in fact reports of children as young as 3 getting it, and it seems that many of the forum members are in their 20s or 30s so the medical profession has it considerably wrong when they say over 50s get it more often! My Rheumatologist (long story!) actually told me that my experience of this pain couldn't possibly be TN because he has looked into it for his mother-in-law and at that time I was only 50!! Many rude words were going through my head, anyhow I shall correct him when I see him next January as I have since been given a diagnosis of TN and the medication has helped to reduce its frequency and severity.
Specifically my pain started in the left eye, it got much worse this February and spread to other parts of my face and head, affecting both sides. I did have stabs of pain over my head and hideous pain in my teeth long before the eye pain started but I think I decided that was due to previous head injuries and as for the teeth I have slightly receding gums and put the pain down to the cold reaching the nerves in the teeth(!!). I had also thought the eye pain was a type of migraine. I had this gradually worsening pain in my left eye for about 10 or so years.
My left cheek tends to tingle and feels numb but with a spikey-footed spider crawling over it just before and after an episode of pain. If it affects my left eye I am totally incapacitated for anything up to 20 hours, and before medication this would be between 4-7 days. Anywhere else, head, face, left or right it usually lasts only a few minutes but it can occur up to 50 - 100 times a day.
So, with regard to the Rheumatologist, I have something along the lines of Lupus or something autoimmune going on and the medication I take for it can affect my liver just like the medications for TN so I have had to very slowly increase the dose. I will be discussing this with my GP this week as I am still getting pain.
Triggers for TN pain can include cold, touch, teeth cleaning, chewing, biting, sometimes movement of the face, as in smilimg, laughing, yawning, others find that lying on the affected side can be a trigger too. Certain foods can apparently trigger it too, such as very spicy foods, cold foods and so on. For some there are no triggers. It is very unlikely that any two people will have exactly the same experience or that that experience will match the textbooks!
Causes vary. Classic TN is due to a blood vessel wrapping around or pressing on the nerve just at the point it divides into the three branches as it enters the face. Other cause can be due to Shingles or other viral infections, damage due to injury, such as head/face injuries, some may be due to illnesses such as MS, in this case it's because the nerve coating (Myelin) has been damaged. There are probably other causes including those within the remit of ENT specialists but to be honest the list goes on.
You do need to be seen by a Neurologist, so ask your GP to refer you sooner rather than later.
Best wishes.