Here is a before/after image split:

 

Knowing how to make good selections is the most important part of using Skin Softener. There are a couple things to keep in mind.

First, it is better to split up your selection if it encompasses a both a dark and light region such as a highlight or shadow. If you use one large selection over multiple regions, the effect might looked flat. So breaking up the selection near a shadow will help preserve the lighting and depth of the image.

In the example below you can compare the results between a single selection across the face and multiple selections (broken up between shadows and highlights). You can see that by using multiple selections, there is more depth to the image.

 

 

Second, watch out for color bleeding. This can occur if your selection boundary goes off the face into the background or crosses over two very different regions such as a dark shadow on the face. The result is the background color being pulled into the selection. See the example below.

 

Here is the original image if you want to try it out.