Use Smart Tone to brighten up an image
Since increasing the contrast introduced more shadows to the image, brighten it up again by using the Smart Tone filter. Dragging the slider to the right brings more light to areas of the image that are dark, without dramatically affecting parts of your image that are already bright.
Below, you can see an extreme version of the Smart Tone slider in action. Notice how the shadowed areas are brightened, revealing lots of detail, particularly in the hill on the right. This is what you can do with Smart Tone, but it’s not necessarily what you should do since the image now appears very flat without any shadows or contrast, and the dreaded halo has appeared again.