pull your fingers back and hold them down to stretch your hand. it will hurt a little in the wrist but let it stretch out for a few minutes. i have the same problem but it orginates from a pinched nerve in my neck.
I got it from hitting a punching bag too hard and at wrong angle. but anything aggravates it now, including jerking it.
I've always wondered if holding your breath and making a wish through carpal tunnel would make your wish come true, or if you'd pass out from lack of oxygen first.
I have good lungs and drive fast so its never been a problem. Never tried it when there was traffic but that gives you brownie points.