Step 9: Add a layer mask
To manually specify where the freckle removal effect should appear, we'll be using a layer mask. Add a layer mask by opening the Layer> Layer Mask> Hide All. This should create a black layer mask that makes the entire layer invisible.
Step 10: Paint over the freckles
First, make sure that you have the layer mask selected by clicking on the thumbnail of the layer mask. It should have a white outline around it to indicate that it is activated. Select white as the foreground color and use the Brush tool with a soft edged brush to paint the affected areas. This will feel like an eraser tool for the freckles because the area you paint is the area that the freckles disappear.
