Had a spot cut off my shoulder years ago, and used my mother's fave, zinc oxide in cod liver oil cream that we used to be able to get down here, never left a scar.
Uncle used it on psoriasis pretty effectively.
So I don't doubt it's effectiveness.
Funny aside, back in the 80s, at a school sports carnival, the girls all decided to use zinc sun protection cream (white) to mimic "Adam and the Ants". Out in the sun all day, and when they washed it off, tanned skin and white streak that stayed for weeks.
zinc is in sunscreen, but for cheap face cream to remove spots and such,,,,diaper rash cream,,,10 percent to 25 percent in it,,,sounds silly, not much for a large male ego, throw out the ego, it works.