I don't think anything will happen to your tattoo...Henna stays on for about two weeks, and hair dye won't do anything to your skin.
you can buy the stuff at an art store
it is a place by tj maxx and party city called heena salon
Its a temporary tattoo made by dye from the henna plant .Henna has been used for body art and hair dye for years.
It darkens it.
How Henna Tattoos Are Made
How to Do Arabic Henna Designs
How to Use Tans for Body Art
How to Henna Tattoo