It's a new Marine Corps now. You need waivers for all tattoos and it will get denied if they are on your neck or hands. The Corps has changed and not for the good now and days.
Oh and I forgot to say its cause when your lose blood pressure you don't get it to your brain and that's why you go night night... Try keeping your legs elevated above your head and you won't have any problems.
Yo... Bro... You nervous? If you are that's probably what happened man. If you are nervous you blood vessels will expand and you can pass out..I used to do it all the time!! You can't help but laugh when you wait up. But here's the deal bro drink lots of water and breathe an you will be fine...