It lasts on average about 2-3 weeks. It will appear dark when you first do it, and then slowly fade away.
A Henna Tatoo last for 3 weeks
most 'peel off' tattoos will wash off with soap and water. a quality henna tattoo can last up to a month and still look good on a person with the right skin type.
forever they are the same as getting a normal tat dude
4 ever