Harmful Sharpie Tattoo?

I really want to get a dark mark tattoo for the premiere of Harry Potter and the Deathly Hallows, but im only twelve so I can't get a permanent one, and i only want it for a day so no henna. If i use sharpie will it affect my skin or harm me at all??? If you know of anywhere that I can buy a temporary dark mark tattoo or any other suggestions, please answer!!! Thanks in advance