I dont know about using grays on the face, it seems too dirty.
The head seems right, but i dont know about the features.
Why not to use reference at this point?
Looks good from the artistic/inspiration side but needs more work.
Maybe the colors are too pinky to me, and the background, dont know.
Well, dont get discouraged from my crit, the girl is looking mysterious and had angel on it, maybe a little features/color tunning will do the job.
And please, remember, the hair pays a big role too, try to express his hair too.
Hope to help! I had done a lot of faces and this face reminds me of that time.
T=ART, ...keep going to that special place, never surrender...