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