How to treat pink skin under scab post TCA. The spot healed, but how do I get rid of the hyperpigmentation? (photo)

I see and hear your concern.  Oftentimes pigmented lesions like this can be successfully treated with the pulse dye laser.  It may benefit you to schedule a consult with a Facial Plastic Surgeon to have an in-person evaluation and treatment for this problem.

I don't recommend doing peels yourself, due to the risk of complications. I recommend getting a formal evaluation with a cosmetic dermatologist for after care and treatment. These spots can be improved with a combination of lasers, Aerolase, microneedling/prp, skin lightening, peels, and skin care. Sun protection is essential. I recommend getting a formal evaluation with an acne scarring expert. Best, Dr. Emer

Hello and thanks for your question. If you are satisfied with the contour of the scar, and pigmentation is issue, I would protect it from the sun and give it some time to heal (4-6 months). Post Inflammatory hyper pigmentation is  a challenge to treat and may require laser therapy as well as continued bleaching treatments. You would benefit from a consultation with a physician. This is a challenging problem even in the best  of hands, good luck.