Henna tattoos are popular with kids because they fade away after a few days. You need to be careful though. Some people have experienced scarring from temporary tattoos, making them permanent. We did some digging and it seems a big factor is the color of the ink. If its done with black ink that contains a substance called paraphenylenediamine, it can leave a scar in the shape of the tattoo. If you ever get a Henna tattoo, make sure it’s done with plant based natural brown henna.
Learn more about it here. http://www.kctv5.com/story/24817733/temporary-tattoos-could-cause-permanent-scarring