You know, I've looked at this a few times over the past couple of days, it's a really interesting shot. My only personal nit-pick is that his underwear bother me, they distract from the tattoo with their plaid pattern. (And, hehheh, I'm just old enough that I plain old don't get the super low hanging pants thing, but nevermind that..)
I keep wondering why you decided on B&W, though. That tattoo must be stunning in colour.
I like how you lit this to give some shape to the features of his back. Like BlackSheep said though, plaid does not go with the tats.
I think nude and more dramatic light would work better.