I have idiopathic small nerve f.n. it hasnt really limited me physically much, but can i still gain muscle by lifting weights? or is it harder to gain muscle mass? dumbbell curls and such can cause some pins and needles?

Neuropathy: Since small nerve fiber neuropathy involves the nerves associated with sensation, not motor function, you should be able to exercise as desired. You can still lift weights and build muscle and you can still gain muscle mass with no problems. You may experience sensory problems such as pins/needles, electric shock sensations, cold, burning, numbness and tingling.