The major difference between hennas and tattoos is how they are placed on our bodies, as well as how long they last. For one thing, tattoos are placed via a needle under the topmost layer of our skin and are therefore permanent. Henna on the other hand, is ink that sits on top of our skin.
Tattoos are permanent and they pierce the skin to carry the ink down to the blood bearing layers of the skin to create a design that is permanent. By contrast, henna is a temporary dye that just sits on the surface of the skin. It only stains the dead layers of skin cells and it lasts about few weeks. Henna comes out darkest on the hands and the feet where the skin is the thickest. And by contrast, the tattoos do not take as well on the hands and the feet because the skin tends to bleed and fade and ruin the tattoo design. In addition, henna is different from tattoo in the style of the art. Henna designs are usually traditional designs from India and the Middle East and North Africa, and they are very different from tattoo designs. But these designs can be made into tattoos.