Paint.NET :: Lighten And Darkening Specific Areas Correctly

I need to know the best way to lighten part of a picture without it being two-toned. An example of this is when I took a picture of someone inside a house.

The orange dress is vivid, and the white wall and door came out good also. The problem is that the lighting wasn't good enough to bring out the true skin tone of the person. So much so that the person's face could hardly be seen, and her neck and hands came out the same as her face also.

I tried to lighten her face by using the Ellipse in Tools>Adjustment>Brightness/Contrast making sure not to go outside the perimeter of the face. I then zoomed to 1600X and manually changed the rest of it a few pixels at a time by switching to the Rectangle in Tools . The result after more than an hour later was something that looked akin to pasting an egg in place of her face on the picture. It was grainy and looked ridiculous.

I don't want to lighten the whole picture because it ruins the true color of the dress, and not as important, the door and walls don't look as sharp and vivid either.

P.S. I would also like to know how to do the reverse; darken a specific area without the two-toned look.