Fantastic painting. The drawing is very good. Some thoughts on how to make the color pop a bit more. (I tried to make a vid but the software kept crashing!).
Blue green gradient in the bg
Dark greyish green in the fabric shadows and dark accents
Same grey/green notes on the darks at the eye socket (see keystone area)
Subtle blues/greys in lower 1/3rds
Splash/hints of red in the face: cheeks, forehead, nose. For more color variety, texture (suggest freckles, skin blemished) and variation in mark making (dots vs strokes).
Subtle variation in brushwork on the cheeks core-shadow that go against the form