Thinking about it, the concept wasn't bad, the execution was. Basically, the nakedness was to show her vulnerability in the whole scheme of things, that she feels defenseless and exposed after what happened to her -- and now for the sledgehammer lick. As weird as it seems, I think it depicts the fact that sometimes going through the pain of it all feels good, despite the bad consequences. I think this is what the director also said but after analyzing it, it's a bit more obvious than before to recognize the symbolism behind it all.