The Rx of 300mg Neurontin at bedtime is probably just to acclimate your body to the med. & see if there are any side effects.
At that minimum dosage, I don't see how it can in any way
affect your symptoms or even touch the pain.
It may help you sleep better, though.
Until you are on a daily regimen of neurontin that keeps a minimum of 1800-2400mgs a day 24/7, in regular intervals of say,
400-600mgs 4xday - I would not expect to see any help.
I was on 4200mgs/day of Neurontin for over 6 yrs when I switched to Lyrica, and am now on 200mgs of Lyrica 3xday along with
a pain killer(Tramadol/Ultram).