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, Desert Essence Coconut, Oribe Silverati
Leave-ins: Curl Junkie Beauti-Curls, KCKT, cno overnight
Styling: BRHG, MGA Sculpting Gel, A-O Mandarin Magic Gel, LOTD AVG, LALSG, CJ Pattern Pusha
DT: Curl Junkie Deep Fix, Briogeo Don't Despair Repair!