@ewi, took me a moment haha hope it helps!
Additionally to the advice above... (except I don't find the eyes to be an issue at all, once you adjust the mouth anatomy.
from her pov, her right eye is a bit far to the side, but alignment wise it is fair!
actually there's a trick when you're unsure. it's a bit like the "mirror the canvas" thing. you cover up e.g. the lower part of the head, if you want to check for the mouth. look at it for a while, and then pull the hand away. when something is off, it'll jump at you)
anywho. what I suspect is messing with it, is that the face oberall is pretty well curved, but the lips are pretty much a flat pane.
but something that's easy to forget: Lips are really three dimensional!
Your jaw and teeth are all in an arc, and the lips cover that.
But additionally, they vary in volume. At the middle the lips are the fullest, and the corners are set pretty deeply.
You don't notice that from the front (which is how you look at your own lips, and conversation partner's), but when you rotate the view, the different volumes overlap each other.
something that shows it really well are good low poly models.
note how you can't even see the model's right corner of the mouth, because the the curverture of the lips overlaps?
to some degree that happens in your perspective as well.
taking a closer look at the geometry will also help with shading. you can find rotatable 3d models online. even with adjustable lights
here's one from art station!
https://www.artstation.com/artwork/6a0Par
the wireframe for the face you already have, disregarding the mouth is a bit different from what yoshiko posted (no offense)
I think you're very right that it's mainly just the mouth that's off.
sooo.... just strictly applying that geometry, and giving the lips 3 dimensions.., it would be something like this (also a bit flawed, but demonstation purposes yada yada)
BUT
this pretty much disregards your personal style and artisitc vision and is strictly structural.
It definitely helps to know how it works, so I do recommend looking at the model and all. but what and whether you applay it once you know it, is just a choice.
there's a ton of ways to styllize anything after all.
lastly, I think your artwork looks really nice regardless, so don't be too hard on yourself or get hung up on nitpicks.
tho a drive for improvement is commendable :3