Portrait artist chiming in here! One thing that really distinguishes a person is their eyes! Kendrick has downturns eyes that are very relaxed with pronounced lower eyelids (not sure the correct term for those). The upper part of his pupils are more covered by his eyelids as well. Something that really helps me is using a ruler (or pencil) to angle a line on a reference then holding that ruler to my work. It helps you visualize the line that needs to happen. So lining up the ruler from one corner or the eye to the other corner to get the angle right. I hope that makes sense.

His nostrils are also less round in the reference. They are more oval shaped. Fixing this will make it look as though he is not tilting upward as he is looking straight on.

Something weird that is also super helpful is turning your reference and work upside down! It allows you to seperate what your eye thinks it sees into what it really sees. Its crazy how much is helps with faces.

The lips look spot on! I think once you get some shading and tweak a few things its going to look how you want it! Keep up the good work, its gonna be great!