Also, after having a closer look it occurs to me that you need to work on your draftsmanship generally. This means that you should, when mapping out your initial sketch, look for shapes and distances more than anything else. Forgot that it’s a face you’re drawing and try to describe lines and shapes as best you can. So if you carry a line from his brow furrows through his naso-labial line you can see a kind of ‘tipi’ shape. try to copy that shape exactly, then measure roughly how far it should be from a break in the line of his cheek. Mark that point, and a few others, then work on getting that line and shape just right. The more you do this, the easier it will be to get everything in the face exactly in the right place.
A good way to check you have the shapes generally right is to close one eye and deliberately blur your vision. This simplifies the shapes so you don’t get so distracted by details.
Another trick you can employ is to look at it through a mirror (or flip the canvas when you’re doing digital works). This makes you see it with new eyes - it’s too easy to get caught up and hyper-focused when you’re working on something, so you miss some really obvious mistakes through familiarity.
Finally, re: what I said about eye orientation, it can be really tricky to get both eyes pointing on the same direction, but since that’s a sign of a genetic defect, people will know if it’s off as it’s something we instinctively look for when choosing a partner or subconsciously assessing how healthy someone is. A good way to check is to cover half of the face and look hard at the eye. guess where it’s looking and fix that point in your mind, then switch and see if the other eye is looking at the same point you just fixed. If not, then it needs fixing.
Hope that is helpful.