Just so everyone knows where exactly I was looking, shouldn't this have an error tag?
With breasts that size, you could assume she'd have at least SOME aoerola(sic) around her nipples, and the way she's turned and pushing against her left breast, it wouldn't be covered by her remaining blouse.
That's no more an error than her huge eyes or tiny fold of skin for a nose, i.e. it's a stylistic choice. Probably in this case to make it worksafe and also perhaps to increase the feeling that it might all spill out. error is for things that are beyond the realms of the artist's choice, like if they have a left foot where the right foot should be.