Create a liquid latex ridge. For a small burn, create a line of liquid latex using a toothpick. For larger scars, soak some toilet paper in liquid latex and shape it into a ridge on the skin using your fingers. Let the latex dry for several minutes until it is firm to the touch.
Coat the latex ridge with foundation makeup. Use a makeup sponge to blot over the latex and blend the color into the skin. Dust with makeup powder.
Give the burn ridge a light pink outline. Use pink blush and a small makeup brush or cotton swab to color the skin surrounding the ridge with pink. The darker the pink/red color and the larger you make the outline, the more serious the burn will look.
Blend the pink color and give the finished scar an extra coating of powder.
Make black burn solution. In a small mixing bowl, combine flour and 1/8 teaspoon of black food coloring with just enough water to create a thick, pasty solution.
Mix some fake blood makeup. In a separate bowl mix corn syrup and four tablespoons of water with red and blue food coloring and cocoa powder. Whisk until fully mixed.
Apply a coat of blood to the skin. Cover the entire area that you want to appear burned. Use a makeup sponge or cotton ball. Let dry for about half an hour, or until the blood makeup is dry and shiny to the touch.
Finish with dots of black burn solution. Apply sections of black flour mixture in dots and streaks over the blood-coated area. Let dry until hard.
Spray the finished burn scar with hair spray. This will help keep the flour from flaking.