There's a whole list of free editing programs which you can find
HERE (it links to another topic on BleepingComputer.com).
As for removing blemishes and whatnot, a pimple can be easily removed with a clone tool (aka rubber stamp tool), or a quick "copy and paste" job, and still look real (unaltered). For removing minor skin blemishes, I'd agree with
projectfocus, a
slight blur will aleviate most skin blemishes (spots from acne, minor sun spots etc.), but don't over do it, or you'd lose the texture of the skin itself and it may appear fake.
I followed the link that
white.funk. posted to her image, and it appeared fine to me. Nothing that make wouldn't/didn't cover up.
ADVICE FOR LINK: You may want to wait until you get home to follow the link that
white.funk. has posted (post #1), as when I was searching for other models to compare her photo to find out exactly what she might be looking to edit out, I found some photos that were not safe for viewing at work (and are definately not safe for this site!). Her photo was fine for viewing though. Of course, this is just my humble opinion.