Not bad, though it really needs a clearer description. It implies it with the title and dances about it, but I think it needs just a little more description. I at least needed to think about it a bit to properly visualize it.
Mental picture shows a guy with his forehead flashing - "This Space for Rent"
And of course, this development is one step away from providing limited chameleon power. Go to Comment
I like the idea of the enhancement, and that the tattoo serves to mark what procedures have been done, but it feels very superficially tied to the tattoo.
The sections also seem a little jumbled - for example the NPC portion just does not flow for me. I think I get the style you are presenting, but it seems to be somewhat split between being serious, and humorous ( Unaltered Humans Against Tattoos), with more towards the silly side. The summary/intro went in a nice, somewhat dark direction but the other sections dropped the tone.