CFS is not a quack DX but interestingly enough Could be a cause of your TN. (or at least one of the forms Myalgic Encephalomyelitisis is. CFS is also one of the very few syndromes that has been studied for LDN there is a slight improvement over the placebo and larger scale studies are being done. So lets hope you are one of them!!
Keep in mind while the quackers talk about FDA approval, it is very a very short term usage, and the risk factors balance against very serious disease (death type disease). The medication has been replaced for the most part with something else. That "safety doesn't transfer to longer term low dose which is why its VERY hard to get low dose dosages.
The problem with adding links etc. is there are none say XYZ DSOESN'T work for ABC and has these problems. When it comes to the "cult drugs" such as LDN the internet SEO is so pammed, that the first 12 page or more for many of these things give only the quacker view. You are likley to end up in a "false News" site like treato where everything is equal - good science or bad. So one can say he has educated himself but its not even close. The real research done is in web pages, its not on PUB Med which includes just about anything good bad or just plain nuts, its almost impossible to find on Google Scholar as well.
Sooooo what does one do? Real libraries (most medical Centers have one) with real journals is a good place to go, Your doc who is willing to admit there are few answers for some conditions has likely followed the research or at least has had it presented in his annual required education hours can point you. Various patient advocacy associations (the legitimate ones) are usually on top of it.
Patient testimony is helpful when it is but very harmful when it is not. People on the forums are generally pretty desperate and outliers of the disease. Those that have gotten better usually move on pretty quickly. They are often highly suggestable and desperate for help. That is WHY these boards are very heavily moderated. We don't want to control discussion but we do want to direct it. For now LDN just isn't a great topic for Facial Pain Patients. I don't hide my prejudices well either