I also have some red spots left behind. I try many things at the same time. Recently I discovered snail cream. I use it twice daily and within 3 days I see much difference. You can also try MSM cream, vicks vaporub, and lavender and geranium esssential oil. The more recent the scars, the easier to go.
If you are comfortable with trying some chemical peels to help with fading that might be a great route. I use MUAC Mandelic Chemical peel as well as their Lactic Acid and Fade Peel. Makeup Artists Choice. They have a ton of reviews, very helpful customer service and if you are a chemical peel newbie they have tons of options. Lactic is one of the safest and highly effective with PIH. Happy Friday and great to hear you have gotten rid of your acne and get to work on clearing up the marks now. Wish you the best.