I would recommend looking for fake blood tutorials, and simply changing the color. If the recipe calls for chocolate syrup, I would also omit that, since it is often more for color than texture. These tutorials are going to be skin-safe and some will partially dry if you hit them with a hairdryer or similar.
If you want something shiny that will fully dry, liquid latex painted around your mouth will give that effect. Be sure you are not allergic to latex before doing this!
I hope this helps! Good luck :]