A tattoo if it is permanent cannot be done anything about. So that should be fine. But do not wear a long sleeved dress. because it needs to be simple with no big buttons or embroidery or metal chains hanging. Wear a light coloured half sleeved kurta with palazzos or formal pants. No jewelry of whatsoever metal will be allowed. And no watches or electronic gadgets will be allowed. Simple sandals are allowed but not shoes. As long as these are followed a tattoo should not be a problem.