I started this Regan from the Exorcist DIY Costume by using a coat of white cream makeup. I used liquid latex and did two layers using white Kleenex where each wound would be. Covered with a gray cream makeup and powdered with baby powder. Tooth wax on the teeth before using scar wax to coat your lips. Used a scar wax and covered with liquid latex on the lips.
Cover entire face and neck with a gray creme makeup. Gently tear open the wounds. Fill the wounds with a light coat of black creme makeup. Use purple and yellows for bruising around the wounds. Fill in the wounds with red creme makeup.Shade in your eyes and anywhere else you want shading with black eyeshadow and use red creme makeup around the eyes. Use black, grey, pink and red on the lips.
Get a good wig. I used a flannel night gown and flour mixed with green food coloring and black creme makeup to make the pea soup vomit on my PJ’s. Bought the contacts online. Contacts make the whole costume.
Related costumes:
Scary Couple Costume from Exorcist: Regan and Priest 
Coolest Exorcist and Priest Couple Costume 
Awesome Homemade Red Queen and Mad Hatter Couple Costume 
Homemade Teen Wolf Costume 
Creepy Homemade Regan Halloween Costume from The Exorcist 
Coolest Homemade Amy the Vampire from Fright Night Costume 
Fun DIY Beetlejuice with Shrunken Head Costume 
Scariest Homemade Samara from The Ring Costume
Oh Yeah, I forgot to say that the best way to conceal your eyebrows is to use a washable glue stick (i used the disappearing purple kind) and cover them using four or five coats. Of course let them dry inbetween coats.
Where did you buy your contacts? I have a perscription and the cheapest effects contacts I have found are over $30.