Create in Photoshop a new layer on top of the Blemishes layer by clicking on the Create a New Layer icon . Rename this layer to Smooth Skin by double clicking on its name in the layers palette.

Hold down Ctrl + Alt + Shift + E (Command + Option + Shift + E on the Mac) to merge all visible layers on the active layer (Remember this Photoshop shortcut, it's a very useful one) or in other words; the layer Smooth Skin will contain the image that was visible in the document window when you used this shortcut, which includes all the corrections we did to remove blemishes.

We're going going to use the Median filter to make the skin look smooth. Some tutorials advice you to use Gaussian Blur, but I prefer median because it takes better care of edges and it's exactly those sharp edges that we want to leave intact as much as possible. To show you the difference between applying Gaussian Blur or Median to our image, look at the following comparison:

Gaussian Blur		Median

Notice that by using Gaussian Blur you're actually moving the blue that's in the background in the skin. This is of course something we want to avoid at all cost.

Now go to the menu and select Filter / Noise / Median... , enter a radius of 10 pixels and click OK. Set the opacity of this layer to 50%:

 

The result:

The skin now looks exactly the way we want it, but by using the Median filter we've blurred areas that need to stay sharp, like eyes, lips, hair, hat, eyebrows, eyelashes and the edges of the nose and nostrils. We are going to fix this by adding a mask which allows us to ignore those area that need to stay sharp.

We add a mask to the Smooth Skin layer by clicking on the Add layer mask icon in the layers palette.

Press the letter D on your keyboard to make the foreground color white and the background color black:
Press the letter X on your keyboard to switch the fore - and background color:

Select the the Brush Tool by clicking on its icon in the tool bar. Check the options bar:

Use the settings that you see in the options bar. Notice that we're going to start with a size 50 brush. This time the hardness of the brush is set too 100% (hard edges). You can change both the size and hardness of this brush by clicking on the little black arrow like we did earlier with the Healing Brush Tool.

Now it's important that you have your mask active at all times before you start using the brush, since we have to apply the brush strokes to our mask and not our image. An active mask can be recognized by its double border (marked with the red arrow) and the mask icon in front of it:

 

To be able to see what we're actually masking, let's turn on the equivalent of Quick Mask by pressing \ on your keyboard. You won't see anything happen, but let's paint on the hat inside the document window. You'll notice that the quick mask mode now marks the area that is going to be masked with a transparent red. Turn off Quick Mask by pressing \ again and you'll see the area of the background layer that you've made visible by masking the same area on the Smooth Skin layer:

 

So that's the whole purpose of our mask in this tutorial, to hide the areas that are blurry and which have to stay sharp. You can change the color and opacity of Quick Mask by righting clicking on the mask's thumbnail in the layers palette and selecting Layer Mask Options... The following window will open:

In this window you can change the color by double clicking on the red square. You can also change he opacity of the Quick Mask color, which is by default 50%.
Note: The opacity setting doesn't affect the layer or the mask itself, it only affects the transparency of the mask in Quick Mask mode.

Continue by turning on the Quick Mask mode by pressing \ again.

Look at this screenshot:

You'll notice that I have masked everything that needs to stay sharp (unaffected by the median filter). If you have a hard time to tell whether you've fully masked those areas that need to be mask, then do the following:

• if Quick Mask mode is on, turn it off
• Alt + Left click (Option + click on the Mac) on the mask's thumbnail (see next screenshot, A) in the layers palette

This allows you to view (or edit) the mask in your document window and will show you pretty precise where you need to make adjustments, like in this case around the left eye:

You can return to the normal view by clicking on the layers thumbnail in the layers palette (B).

To create a clean mask you have to use the following guidelines;

• Change the brush size often. Instead of switching to the options bar several times we're going to use a shortcut; press [ on your keyboard to decrease the brush size or press ] to increase its size. There's also a shortcut for hardness; press Shift + [ to decrease the hardness of your brush or press Shift + ] to increase the hardness.
• Mask large areas with a large brush and a hardness of 100%.
• Mask small areas with a small brush and a hardness of 0%.
• Mask accurate edges by using a large zoom factor and work with a small brush, low hardness of 0% and a low opacity (about 30-50%).

Also make sure that sure that you don't forget to mask areas like the corners of the mouth, fine hairs, eyebrows, eyelashes and the contours of nose and nostrils. For those areas try to use a soft, small brush with a low opacity.

This is the final result (after some slight sharpening):

Important: Give your browser enough time to download the "after" image or you won't see any difference

 

Note: you can reduce the strength of the effect by lowering the opacity of the Smooth Skin layer.