Elaborate? benign leukoplakia removed form vocal cord 1 mth ago. shows big post-op scarring. voice ok, worried about turning cancer later. unlikely?

Yes: Benign leukoplakia would be benign and no dysplasia means it's more like a callous of sorts.

Remain watchful: Leukoplakia is a precursor lesion which can evolve into cancer in a small minority of people. But once it is removed then there is minimal risk of that change. yet you must be checked by your ENT doctor periodically. This is an easy area to monitor yet any change of voice will require you to get checked. By and large you are expected to do well. So remain alert yet not worry too much.