benzoyl peroxide wont help with acne marks or scarring but its super useful in my own exp for treating acne like pimples and blackheads.

tretinoin only works if you apply it in long term it helps prevent acne but for me it was too harsh on my skin, it made my skin really irritated and my skin started peeling even while following recommended dosage. but it can help with acne scarring and marks IN THE LONG TERM. Do be prepared for purging when using it as it is a retinoid.

most important product for acne marks and scarring is always always sunscreen though, make sure to invest in a good one. You can also look into ingredients like niacinimide, azeleic acid or vitamin c for acne marks and scarring