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.
When locations as lethal as this are brought up, I have to wonder about how they would be used in play? Complete obliteration from one wrong move? Lost, sure, but unrecoverable? Of course it is easy for a GM to change to suit their own game.