In English, there are no useful words to describe a mehndi / henna stain ornamenting the skin, so mehndi / henna are frequently called "Henna Tattoos". Hennaed skin is not tattooed. A tattoo is a permanent design in the skin, made by forcing pigment into the underlying layers of the skin, usually with a needle. Mehndi / henna is a dye that colors the outermost layer of the skin. It does not go into the blood bearing layers. The skin is not pierced. It will not bleed. It can not hurt. It feels about like having your skin decorated with pudding.