Suspect VFX Supervisor/Lead Flame Artist Tim Crean created the detailed VFX lace that grows across Christinas back in Select's ad for the Procter & Gamble celebrity perfume.
You might have already seen it, this spot has been airing in Sweden for the past two weeks and is planned to air worldwide. Maybe you sense a deja vu if you recall this 2005 commercial where a nude Gisela grows an entire body tattoo. Not that I'm saying they're similar or anything, but yeah, that whole hot nude chick grows tattoo effect has been done before. Not the fault of the post house mind you.
See the new Christina Aguilera Signature Fragrance commercial here.

The spot's main focus was the tattoo that we would "grow" on Christina's back to look like the bottle of her new perfume, which would then be sprayed onto her body. This required extensive animation tests - the large tattoo had to grow quickly, but not feel aggressive or malevolent. Next came the spray mist, which was a little tricky in that we were animating across a moving surface. We constructed several CG tests first with Particle Systems, then the directors shot practical elements for the mist to be incorporated with the live-action. The most challenging aspect of the process was that the tattoo had to move with the angles of her back. Very similar to a recent project we completed for Eucerin which married imagery with skin in a feminine, beautiful way.

Yeah, making tattoos not feel aggressive seems like a tricky balance, you could have asked post house Conspira Digital in Brazil for advice mind you, as they did it quite well. ;)