Help needed: First AA atempt

[ABC]

Hi, so this week is my first time trying to enter PixelJoint's weekly challenge.

I'm remaking this piece:



I'm trying to AA but even in greyscale it looks ergh... (on the right is a sketch of the mouth and how the colors might look)



Help is truely appreciated. I quite like my design (original sketch) but if you have any suggestions feel free to let me know.

[pistachio]

The problem here is that in most places you're only using lighter shades to bridge the gap between the colors. The outer AA (dark blue to BG grey) could use an extra shade as well, while you're at it.

That bit highlighted in green is an example of what would yield better results. In this edit I tried to apply it globally.



Quick example of cleanup and AA on mouth is also there.