To get sharpie off your skin fast you can use some rubbing alcohol, nail polish remover or even hand sanitizer.
Take either the rubbing alcohol, nail polish remover or hand sanitizer and rub it on the area where the sharpie is.
When you rub the nail polish remover or the hand sanitizer or rubbing alcohol on the skin over the sharpie mark it will remove and dissolve the sharpie.
Then just wash your skin with some soap and water.
It might take a few tries to clean the sharpie off of the skin but it will come off with the the above things.
Or you can also rub some olive oil, baking soda or even salt on the skin over the sharpie mark and it too should remove the sharpie from the skin.