you can buy some of that wetsuit repair **** they sell it in a can. Must be a rip to the runner which case this **** works great. i use it all the time on little holes
yeah what they said. that neoprene cement is great. got a fin cut on my new suit not long ago and was pretty bummed. the neoprene cement turned my frown upside down.
Before I trash old suits, I cut off pieces for repairs... like the flap behind the sipper, which makes good patch material. I'll also pull off strips of tape and save some of that, too. For the record, I NEVER sew wetsuits... some guys do, but I don't. I just glue and patch them.
If you are determined to sew it, use the FLAT strand dental floss then apply neoprene cement and a little patch/tape. I think it's an unnecessary step, but whatever is the most cathartic for you.