Photoshop CC 2015 tutorial showing possibly the best technique to retouch skin in a photo. “Frequency Separation” retains the skin’s texture, while it removes blotches and imperfections.
If you want to remove unwanted things on the picture with AI, check out AniEraser: <a href=" Photoshop CC 2014 tutorial showing how to retouch a face resulting in beautifully smooth, flawless, skin.