I am so sorry for the pain you are in. Trigeminal neuralgia is said to be the worst pain known to humanity. I developed TN after a case of shingles. The TN attacks sent me to my knees screaming and crying in pain. 1800 mg of gabapentin a day stopped the intense attacks, but I feel the opthalmic part of the trigeminal nerve, like it is moving, several times a day, but painlessly.
The microvascular decompression (MVD) surgery is a cure for TN, but only when the TN is caused by the compression of the nerve by a blood vessel. I believe an MRI can show the compression and should be read by a neurosurgeon, not a neurologist, because a surgeon is more experienced usually.
As I understand it, the shingles virus can damage the trigeminal nerve as it moves along the pathway. This is what happened to me, so it is not a compression, so MVD would not help.
I actually had an MVD in 2005 for a condition called hemifacial spasm where there was a compression on the 7th cranial nerve causing the face to spasm. I had the condition for 4 1/2 years and the surgery cured me. I went to Pittsburgh from Texas to have the developer of the MVD, Dr. Peter Janetta, to do the surgery. He actually supervised as there were multiple MVD surgeries going on at the same time and he moved from operating room to operating room. Dr. Janetta first operated on a TN patient and cured him. He continued to operate on TN patients until he began speculating that hemifacial spasm might also be the result of a compressed nerve and began curing that condition with the MVD surgery.
Have you been on the medications for TN like oxcarbazepine and others? I tried that one, but did not want to be a zombie, so went back to gabapentin. With how bad your pain is, being a zombie might be preferable.