Instructions
Press the "Start" button in "Metal Gear Solid 4" to bring up the "Pause" menu.
Select the "Camo" sub-menu. The menu that appears on-screen will detail all of the different types of camouflage that Solid Snake is currently wearing.
Select the "Face Camo" section. This will show you all of the different types of face camouflage that Solid Snake can wear. Use the menu to select a type of camo by name.
Press "X" on your PlayStation 3 controller to change Solid Snake's current face camouflage from whatever he was currently wearing to whatever you have chosen to wear. Press "Start" again to return to the main game.