Short and sweet idea, incorporate the ability to add coded colors into descriptions and tattoos, much in the fashion of how paintings and clothes already work.
That's it.
Since those are body parts which take colors.
Complexion comes in colors, too, but not ones well supported by ANSI colors. White, black and brown are all rendered in %normal text, and I don't even want to get into %red or %yellow options :)
I also would love to see black be a deeper shade of the %normal text so it stands out more.
I know all these things are just aesthetic, but when not overdone the little color bursts in a description really draw the eye and would make a tattoo that SHOULD stand out, actually stand out. Maybe?