Will mederma work for a cleft palate scar?

No!: Mederma is simply onion extract. It has been studied and has absolutely no effect on scarring. It's only effect is hypersensitivity in a small percentage of people. Massage will help and possibly revision with time.

No evidence of that: There is no good evidence that Mederma has any effect on scars. The only agent that has some proven effect is silicone taping, which is probably a very bad idea for children as they are likely to swallow some of it. As you know from the news, silicone is not something we want in our bodies!