Soften a piece of sugarless bubble gum by rubbing and moistening it if you need to. Form wounds on your body in the desired shapes.
Mesh the gum with your skin on the edges. Make slices or gouges in the middle of the scars using a butter knife or other sharp tool. Separate the slices or gouges to make them more jagged and natural looking.
Apply skin tone makeup to your scars—it’s easier if you use a moistened makeup sponge. Powder makeup works better than liquid.
Leave the scars as they are if you want them to look aged. If you want them to look fresh, put some black makeup inside them. Then add some blue on top of the black and some red on top of the blue. Use powder or Halloween makeup for best results.
Blend some fake blood with corn syrup and red dye. Or, buy some ready-made fake blood. Apply the fake blood to the scars.