You will need
Clay, milliput other sculpt able medium
Spray primer or gesso
White satin spray
Acrylic paints relevent to your colour scheme
Hair dryer (optional) but helps drying paint.
Step 1: Prep the V Mask
The surface of the v mask should be sanded down to removes the surface paint (not details) this is so the primer will stick to the mask.
Step 2: Sculpting Scars
I used milliput to sculpt the scars and muscle strands onto the mask, i wanted the realism if the dark knight harvey dent with the added comic persona of the batman animated harvey so i used both as reference.
Step 3: Prime
Prime the whole mask grey and then mask one side off and then paint the scarred side black.
Step 4: Paint
Begin to paint in details on the scarred side.
Step 6: Painting the White Side and Weathering
Now re paint the white side adding any scrapes or other details you like and then wash over it with a vert watery brown acrylic and use kitchen roll or paper towels ( not tissue) to wipe the mixture into the groove and away from the larger areas. It should look more realistic and not plastic.