Will zinc oxide help remove skin discoloration due to scars?

No: Zinc oxide is a physical sunblock. It will not change the color or texture of your skin or scars.

Yes: Zinc oxide is a barrier against uv rays. It will minimize pigmentation in your skin from the sun. If darkened skin is your concern it will help. If the scars are red time will help these areas to resolve. However limiting sun exposure is preferable. If you can't avoid direct sun light then zinc oxide will help protect the skin.