Too much dithering on the hand and forearm. The way the hand is holding the flower, I think all you would see would be the very finger tips and not so much else of the digits. The thumb is bent down on the palm and not having anything to do with holding the rose stem, you should fix that. The arm/hand has too many jagged pixels.
I can see a hint of color theory was planned in the product, but they weren't put together very elegantly. For instance, on the rose, you have a yellow/orange highlight meeting a black outline, this is jarring to look at.
EDIT: The yellow background is way too bright and saturated and does nothing to help the image.