In my experience, AHA (alpha hydroxy acid) products or rosehip oil have helped to lighten my ace scars over several months. I've used Alpha Hydrox, MD Forte, and Alpha Glycolix products (not at the same time) with good results.

The rosehip oil I'm currently using is Pai brand and I like it so far.
Location: Texas
Type: 3b/3c (i), below shoulder length.
CO wash: A-O GPB LYY, Salon Care Honey Almond, Devacurl OC, Acure Argan Stem Cell+Argan Oil, Mill Creek Botanicals Keratin Repair
Leave-ins: BWC, KCKT, cno overnight
Styling: BRHG, MGA Sculpting Gel, A-O Mandarin Magic Gel, LOTD AVG, LALSG
DT: Kiehl's Olive Fruit Oil Deeply Repairative Hair Pak, Curl Junkie Deep Fix, Briogeo Don't Despair Repair!