Well done. I would also say the whole area around the belly button does seem to be a little too concave. I would think that there should be a little darker value under her breasts, imho. They seem a little flat (not that way!
) I like the tag on the underwear, but it may be a little too bright. It sticks out just a little too much. I think if it was a little darker, it wouldn't stand out so much from the piece and be more of an "easter egg" to be found. The hand, especially the pinky, does need a little more refinement. It looks too thick right now. All of this is just my opinion tho. I'm still learnin'.
Love the face and skintones, and of course the duck!
You must have faith in yourself when no one else will....like now for example.