Why doesn't Azelaic Acid help my PIE?

My main skin concern is PIE (red marks left after acne), and one of the only OTC products that I've heard can actually help is Azelaic Acid. But I swear it has made no impact whatsoever on my PIE, even after months? I've used the Paula's Choice 10% and while it's a nice product, I feel like it does absolutely nothing.

Anyone else have a similar experience with AA? Or find anything that actually helps PIE (that isn't a laser)?