Here’s a quick fix that I use to reduce shiny foreheads in headshots (and portraits) using Adobe Photoshop.

Step 1 – Create a new layer above the background layer by clicking the New Layer Button (or CTRL+SHIFT+N on Win / CMD+SHIFT+N on Mac)

Step 2 – Set the new layer’s opacity to 30%

Step 3 – Select the Brush tool

Step 4 – Alt+Click on skin near the shine to grab the skin tone color

Step 5 – Brush over the shiny area with a soft brush

And you’re done!

If you want to speed up this process even more, you can create an Action that creates the new layer, sets the opacity to 30%, and then selects the brush tool. Then all you have to do is run that action, select the skin tone, and then start painting in the shiny area.