Using the Spot Healing Brush, Healing Brush and Patch Tool

Before

After

Spot healing brush automatically gets rid of any blemish, but does not work well when you use it near an area of skin with very different colours.

The healing brush is a better because it allows you to select a sample to clone from, blending it in with the original picture.

 
Edit - Fade Healing Brush 
to retain some of the original image