In principle, the above edit works - those steps will get you the results you want, but the implementation is the hard part. The trick is not to brighten the shadows, but to brighten the shadows realistically. What the above edit fails to take into consideration is that there is still a shadow under her right cheek. That shadow identifies the light source as "above right" to the subject, but the new brightness on her other cheek says the light source is to the left of the subject.
When you do this, it is very important that you do not introduce conflicting lighting cues like this. The steps that hawkeye60 describe are correct, but the when you use them, make sure that you are not so tunnel-visioned on the shadow that you fail to consider the whole shot.