Hope its okay I suggest something. I dont know Gimp, but I hope you can find more or less the same feature in that program, I use Photoshop.
The small well... pimples, I would remove. Not to make her look like a doll, but just a bit. And I would do it like this:
Find the clone tool:
Right next to the pimple you hold ALT key down and click with the mouse, to let the clone tool know, that is the skin tone you want:
Then you just release the alt key, and place your clone tool on top of the pimple. Click - removed.
Maybe you have to click twice, but normally not. Then you go to the next pimple you want to remove, hold ALT down right next to it and clone again.
I just removed a little, hope you can see the improvement.
And then I took a little yellow out of the picture and gave it more contrast:
Think your portrait is good