Fair skin, female - what can I do to lessen the appearance of white acne scars on my chest? (Photos)

None of the approaches already tried had much chance of success. You would be wise to consult with a board certified cosmetic dermatologist about the professional use of Dermastamp microneedling for each of the spots accompanied by the application of prescription pigment promoters, such as topical tyrosine and lanatoprost. Hope this helps.

I have developed a protocol to repigment hypopigmented scars if there are remaining melanocytes that are actice. Plasma laser is key.

Best,
Dr. Karamanoukian
Realself100 Surgeon

Hello!
I'd recommend CO2 Fraxel laser treatment. There is clinical evidence (below) that supports CO2 Fraxel treatment to help improve hypopigmentation like you are experiencing.
You can try other options such as Microneedling, chemical peels, and Rentin-A which can also yield results, but I'd stick with what we know works and go with the laser treatment.
Best of luck!Dr. Tom Korkos