DermaHeal silicone sheeting should overlap scar by about a quarter inch. Problem scar prevention is always preferable to addressing a scar which has turned keloid or hypertrophic. By starting DermaHeal treatment early (two weeks post occurrence or when the lesion becomes dry) you will not only prevent problem scarring but you are more likely to end up with a more aesthetic looking scar, with more even coloring without hypo-pigmentation (white) or hyper-pigmentation (dark) as well as smooth texture.