Step 1: Get Yo' Stuff
Pictured here are all the materials, and I'll list them below to tell you what I used them for.
Background face color:
White and green to give that skin a nice necrotic look. You can also dust a little corn starch over the paint for a crustier look.
Black and white facepaint.
Black, purple, yellow, and green facepaint.
Red facepaint as a base.
DIY face blood made with corn syrup and red food coloring. This is a super simple recipe- 1 drop food coloring to every 1 tablespoon corn syrup. You can even add a little cocoa powder for a darker color if you'd like.
Liquid latex and toilet paper.
Scabs and scrapes:
Liquid latex, coffee, and/or oat meal.