I think, if I were in your shoes, I would make one of the two choices:
1) decide what kind of direction I am taking with this piece and do all the necessary practice and gather all the necessary references I could, then practice until I am satisfied with my skills.
2) Draw naturally and draw the way you feel comfortable, and draw a face that you consider to be beautiful, then compare it to a reference photo (not a 3D model or a muscle chart, but photos of real people.) Then see where you have gotten wrong and see what you can do to improve (which might take you back to option 1 a little bit.)
Either way, whatever you do, I think it is important not to lose your original sense of beautiful and artistic feeling in the midst of references. Unless your goal is realism and this face is supposed to be an exercise to realism, you shouldn't be afraid to draw a abstract or stylized face, which I believe was what you were going for.
It wouldn't hurt to learn more about drawing a realistic face, though, so what you are doing here is also cool. I'm just under the impression that this might not be the direction you originally headed for.