My light switch's wiring is loose...?

Ok, I've read everything up to sugarman....and now I'm gonna tell you what really happened. The screwdriver came in contact with a hot screw and the metal of the switch or it could have been the side of a metal box if the switch was in a metal box. Either way......electricity went from the source to ground. You DO NOT WANT to be grounded when messing with electricity. You want to be isolated from electricity. Electricity wants to be used or go to ground and you do not want to be that path to ground. It only takes 0.06 amps to stop your heart.....less than what it takes to light one single Christmas light bulb. Luckily, in your case, the electricity ped from the hot screw, through the screw driver and to ground instead of through him. He should consider himself lucky and next time......PLEASE.....turn off the power before messing with electricity, especially because you don't know what you're doing. Also.....white wires aren't always neutrals. They can be "switch legs" (hot wires feeding electricity to switches)