Henna is a ground leaf (similar to tea) that, when mixed with an acid and a sugar, creates the paste used to decorate the body. Other things are added such as essential oils. The art form is ancient and holds great significance in many cultures. Today henna has left the confines of the Indian wedding and is offered at parties and fairs as entertainment and is used as a test for a permanent tattoo. It usually lasts about 2 weeks and is safe.
If you have a reaction to lemons or some of the essential oils used, skip the henna and go for a glitter tattoo or facepaint.
I also offer jagua which gives a black stain that lasts about 2 weeks. It takes about 8 hours to show up, is a bit harder to control and is often used with stencils to control the design. It can truly replicate a real "black" tattoo and it's a hit with the boys at a party.
I do not offer black henna. Black henna is mixed with ingredients that can give a serious allergic reaction. Most people don't react but if you do, it's possible you'll wear the design the rest of your life as a scar. So, no black henna here.