I agree with what the others said, I really like the color-palette. I also really enjoy how you used the gradients on the eyes and necklace, it makes them stand out more from the rest apart from just the different colors. I also like the way you did the shadows and highlights, though it´s not entirely clear where the light is coming from (which isn´t necessarily a bad thing!)
The simplicity of the background bothers me personally not much, but I do agree with
Vulpes on the point that the color you used for it doesn´t show up anywhere else in the picture. Maybe you could use another light shade of grey or something purple-ish instead of something entirely new. (though wait, correct me if I´m wrong, but is it the same color as that of the highlights in the necklace?)
But overall you´ve improved a lot since the last picture you posted! Good job, and welcome back!