you may have some pain tomorrow from tensing up and moving the needle around. think about that needle inside the muscle, and the needle tip moving side to side, cutting fibers. i notice zero pain whatsoever when pinning my thighs but every once in a while itll hurt alittle the next day. the main thing to keep it from hurting is keeping the needle straight and not having any side to side motion. needles are kinda scary looking to me too, but once you pin them, its usually not that bad. ive used up to 22x1.5s