This is a photo I found on Flickr recently. The original image can be found here. Since I've been playing with photo retouching, this was the first of many photos that I am was using for practice. This girl cleaned up very nicely. First, I removed the black mark from the forehead. I'm not even really sure what it is, but it was really hard to get rid of it since it was so big and it wasn't as easy to blend the skin tone. Up close it's kind of grainy, but overall, it's pretty decent.
Secondly, I attacked the blemishes on the top lip and between the eyes. They were both pretty simple, since they were tiny little marks that were relatively easy to clone and smear out. The one below the lip was a little tougher, there isn't much light in the picture, and consequently, it's harder to match the skin tone just right. But ultimately, I was able to buff it out.
The next step was to get rid of the date. This looked like it was going to be challenging, but since the hair is not as finely detailed, this could be done again with the clone tool and then the smudge tool.
Next I added a lot of light to the picture. Since it was so dark, I did this by adding a second layer to the photo and lightening it up big time. Then I could reduce that layer's opacity to make it a little less bright.
For my own entertainment, I made her eyes blue, because, well, I wanted to. There was no actual correction here, but I used the "filter pack" that is part of Gimp to pull this off. I used plain old blue, because the cyan or purple eyes I wanted to give her just looked weird.
The final steps involved some other minor skin touch ups. The reduced a few of the freckles just to present a smoother skin tone.
Just for kicks, I also got rid of the lip ring, even though I kinda like it.