Joker & Two Face
This 3D wound technique is the basic how-to you need to create broken noses, cut eyebrows, and busted lips. In addition to what's already in your makeup kit, you'll need a nontoxic glue stick ($1 for two). Cut off a small segment of the adhesive with a butter knife and apply to the area where you want the laceration.
A Glasgow smile (also known as a Glasgow grin, or Cheshire grin), called by people in Scotland a Glesga smile, is a wound caused by making small cuts on the corners of a victim's mouth, then beating or stabbing them until the muscles in their face contract, causing the cuts to extend up their cheeks to their ears. This leaves a scar in the shape of a smile, hence the name.