Are you referring to theobromine? Because the structures are slightly different (although I imagine they were aiming to have theobromine on the tattoo).
Of general interest for future use: ChemSpider is a free chemical database that you can search a number of different ways (structure, formula, common names, and so on).
In particular - I searched for this particular compound (which is, as Ygggdrasil notes, is probably meant to be theobromine) - wasn't able to find an exact match (and the skeleton match was taking forever. Or the window just timed out and didn't update me).