I have friends who got blacklight tattoos on the backs of their hands right after the FDA approved the ink. It shouldn't hurt any more than the any other tattoo as the process of applying the tattoo is the same. As for the safety factor, I don't think there have been any long term studies done on these. I can't say one way or the other as far as that goes, but I can tell you that is why a lot of artists won't use these inks. Also, tattooing with an ink that goes on transparent would be a pain. You wouldn't be able to see what you've already done...