The person will wake up and be disoriented, confused, and may not be able to respond to you for some time, but try and reassure them. Try to get the person on their side-the recovery position in case they vomit. When they do start to come out of it, they may be embarrassed. Please don't stare too much and make them feel even more self conscious.
My hope is that you'll never need this info but at least you will know what to do!