Lightening:

1. part of the cat's face seems to be a bit dark, so we are going to lighten it .

2. From the Layers palette open the Curves adjustment layer.

3. Don't change anything and click ok.

4. Open the Screen blending Mode ...

5. ... which will lighten the entire screen.

6. From the menu bar open Adjustment > Invert .

7. Reduce the opacity of the layer to 50%, then take a soft brush ...

8. ... set the foreground color to white and paint over the area you want to be lighter.