Great question. I wish I had a quick fix for you on this one. The answer to what will work really depends on your child. What works for one, doesn’t necessarily work for another. For some, a simple, honest explanation is enough. If I told my 5 year-old that picking her scab will cause a scar, she’d stop in a second (she has a death fear of anything leaving a mark on her). For others, use a dramatized story of worst case scenario (albeit unlikely). If I told my 9 year-old that picking his scabs would leave a scar, he would not be deterred. However, if I told him, “Don’t pick your scabs because it can cause an infection. To treat that I may have to inject the sore with a big needle and then use a sharp scalpel to drain the infection.” The prospect of that sort of pain would stop him. For others, just creating a simple deterrent is enough—simply cover the scab with a big bandage so the child can’t pick at it. Best of luck!