The tattoo itself says “All the difference in the world” with the iconic 3 stars from the HP books. :D
The quote comes from this passage: “It was, he thought, the difference between being dragged into the arena to face a battle to the death and walking into the arena with your head held high. Some people, perhaps, would say that there was little to choose between the two ways, but Dumbledore knew - and so do I, thought Harry, with a rush of fierce pride, and so did my parents - that there was all the difference in the world.” ~from Harry Potter and the Half-Blood Prince, page 512
The tattoo was done in October at Tribal Rites in Longmont, Colorado.