When BanSidhe did the scar on Noble (her first attempt btw) she used low heat hot glue and molded it to suit her. Then she applied his faceup. That was about 5 years ago, I think, and it still looks great!
Kiki-chan78 also used that method for her two burn scared mod dolls. It lasts very well.
It's all about Hazel!
"Space.... the Vinyl Frontier. These are the voyages of the Starship Obitsurprise. Her 1/3rd scale mission: To seek out new plotlines, to explore the Whole Apartment - To Ball-Jointedly go where no doll has gone before!" -- Swan