Hello! I love the background and the profile shot lots! I also like colours that you chose for it.
However I have few advices for you on how to make things appeal more 3 dimensional.
First of all the key is to understand the shapes\volumes. What I mean is -> you have to account that face is not flat and it has convex and concave parts in it, it also has fat tissues and muscle tissues and folds that are combined in our facial structure. And to represent it better on the picture you have to use variety of tones and hues. Darker and lighter, redder or more orange etc.
I did a paintover to show you how I would chose colours for skin to show "depth". I can also recommend you to use a reference whenever you can and you dont necessarily need to follow the same facial features but it will help you to understand how volumes are built.
I usually throw a black and white gradient map on top of my layers to check the value depth and see if the picture "reads" well.
Im sorry if i changed some features not to your liking but i was trying to give a decent example of depth and volume
Here is a good video of how to approach skin painting - the point that i mean starts around 5min 50 sec
I would also recommend this one - or any other of her video critiques, she explains how forms work and demonstrates it and just seeing her do it and repeat it all with her, i personally found it very helpful
I hope this will be somewhat useful for you
If you have any more questions I'd be happy to help