Blisters forming on skin painted with a black henna tattoo on the arm of a young girl. Henna is commonly used to stain skin or hair orange-brown, but chemical dyes can be added to turn the colour black. These extra chemicals can cause allergic reactions and chemical burns. These blisters may lead to scarring and sometimes affect the natural colouring of the skin.

The chemical responsible for these reactions is paraphenylenediamine, which is also widely used in permanent hair dyes – but its use in these products is strictly controlled. Temporary tattoos, which are drawn or painted onto the skin and then fade over time, are becoming increasingly popular.

http://www.wellcomeimageawards.org/2016/black-henna-allergy

It still looks pretty though. I thought is was somekind of beads glued to the arm.