I've been taking gabapentin for a couple of years now and for about 6 months I've had this rash on my lower arm that don't itch or anything. It comes and goes and after I moved, it took about a month for me to get my insurance in order so I had to go without my gabapentin during that time and I noticed the rash never appeared. Now that I'm back on my med, my rash has come back and now I have it on both of my lower arms. I have no idea what it is.