I take 900mg 3X a day of gabapentin for a total of 2700 mg. It really really helps with nerve pain.
I haven't gained any weight on it, but I monitor my food intake very carefully. I don't think it makes you gain weight per se, but makes your appetite increase. So as long as you know what your food intake is you should be OK.
Corina
I take 300mg Neurontin at night for Migraine prevention and have gained 5 pounds on it over the course of 6 weeks. I hope that that the weight gain will taper off.
I would say that it's going to be a decision between nerve pain and weight gain. If the pain is bad enough that you have to take something, well, there you go. There are some more surgical options, such as a nerve block, that will help, but it's quite a bit more drastic than neurontin or lyrica.
I would talk to your doctor about your weight gain concerns. I would say try it for a while, and see if it helps. If it doesn't work, and you're gaining weight, then you can think about other options.