Preview:
Step 1:
Save the image and open it up in Photoshop.
Step 2:
Select the Healing Brush Tool 
. While holding the Alt key, click on a smooth area of the skin to sample from. Release the Alt key and click on areas that require touch-ups, as shown in the diagram. You can use this technique to remove blemishes, moles, pimples, etc. It is important to remember that when sampling, use an area that has a similar tone/lighting or the results will look unnatural.
Step 3:
Repeat the process until you're happy with the clean-up.
Step 4:
Next, we're going to work on the overall skin quality. Select the Lasso Tool 
and draw a selection around the face.
Hold down the Alt key and draw around the eyes and lip area to remove those area from your selection. Your desired selection should look something like this:
Step 5:
In order to make the selection look natural with the unselected areas, we want to include bits of the surrounding area using a feather selection. Go to Select > Feather > 5px, the press OK.
Step 6:
Right click on the selection and choose Layer Via Copy. A new layer will appear on top of your current layer.
Step 6:
Go to Filter > Noise > Median. Enter 2px for Radius then press OK to apply the change.
Your results should look something like this:
Step 7:
Change the layer mode to Lighten, to have a more subtle effect.
And the resulting image should look much better!
Step 8:
We're also going to touch up the eyes to make the eyes brighter and clearer. We'll also change the eye color. Begin by clicking the original layer with our photo.
Step 9:
Pick the Lasso Tool, and draw selections around the eyes.
Step 10:
Right click on the selection and choose Layer Via Copy.
Change the layer mode to Screen and set the Opacity to 30%. The eyes will appear brighter.
Step 11:
Next, we'll go change the eye colour. Go to Image > Adjustments > Hue/Saturation with the following options:
Step 12:
As a final touch, we'll change the tone of the image. Create a new layer from the Layers Palette. Go to Image > Apply Image. Click OK.
Step 13:
Set this layer mode to Soft light and Opacity to 30%.
Go to Layer > New Adjustment Layer > Color Balance, and use the following options.
Final Results:
