@sunohonmy
I firstly thought it was racism, but then I realized they are probably talking about the skin life, as if he had a layer of dead skin that has been darkened, not about racism.
I have a skin problem, and once I broke my arm and couldn't hidratate it, and when I took of the plaster my skin was just like his.
@Lingik nah, the Chinese have a fetish for light skin, it's seen as more high class. Though in the main characters case you are right, he shed his old skin which has impurities in it.
But overall the Chinese look at white skin as a symbol of beauty.