First things first, create the general shape of the piercing. My tool of choice is the pen tool. For this tutorial, it’ll be a stud piercing, so I’ll need two shapes, one below the eyebrow and one above. This is my basic shape.
Right click with the pen tool and choose Make Selection… Then make a New Layer (Ctrl + Shift + N) and fill the selection with white (Alt + Backspace).
Now we get to have some fun with layer effects. To get to the layer effects window, right click the layer and select Blending Options… Here are the settings I used:
You may also choose to refine the shadow effect by using the burn tool on the skin below the tattoo, but that is not necessary in this picture.