Retouching your skin in photoshop can be tricky if you're a beginner. But don't worry. Here is how i do it : 

Step 1 : Open file with the photo that you want to retouch.
Step 2 : Select The Spot Healing Brush
Step 3 : Set The Spot Healing Brush To "Content-Aware"
Step 4 : Click On The Skin Blemishes To Remove
Step 5 : Save as JPG file
Done.