Really nice head mate...... overall head is in good proportion.
Few areas you might want to look at are.
1) Ears where they join the head... the postion is good, just need to smooth out the transition from cheek to ear.
2) bottom lip seems a bit od. just pull a bit of it out .. its just seemd to far in.
Great stuff, keep it up....
Kurt
I am enough of an artist to draw freely upon my imagination, knowledge is limited, imagination encircles the world. (Albert Einstein)
https://www.artstation.com/kurtb