You appear to be making up some shades (temples) and angles/widths (forhead width, eyebrow angles). I'm not saying thats wrong, because the artist's job is to be more appealing than life (this is debatable, I believe, but I'll say it anyways because I've not a lot of time to think about it), I'm just saying you should be aware and know why you're doing it, and if you really want to deviate from the image in the way you are.
I'm really impressed with your overall technique, I'll make sure to keep checking this thread.