I have seen nobody post an argument as to why it is makeup.
The rules of the competition only allow for the use of editing to prep the image, touching up a portrait is acceptable, but the changing of the skin so dramatically in Post would most likely be considered as excessive in the category it's submitted to as it's not Creative License, it's Fashion.
On the Retouch Pro thread there's some David Skyler retouches linked to which were shot my Melissa Rodwell, David has also retouched similar pure porcelain images, Swarozski Apple campaign, but they all started from a pale model with white makeup.
On the Porcelain Doll image, the amount of edge work to cut in the mask around the flowers, net, hair etc is quite substantial, and would take more time than the 10 minutes it would have taken to put white make-up on the model.
You asked originally what's the post production in the shot, and also for some insight into creating that shot.
It's not a case of you can't recreate something similar in PS, but that's unlikely what's happened in the image you liked to.
The question "how would I recreate this in Photoshop?" would probably have generated a different discussion, but that's not what you asked
