Hello J,
Your picture is not very clear but it does look like post-inflammatory hyperpigmentation (PIH) marks from old acne.
Use of topical retinoids such as tretinoin or epiduo may help but they usually take a longer time to work.
I prefer to use a combination of bleaching agents (hydroquinone/arbutin) and laser treatment 1064nm wavelength on the spots for quicker results. As Dr Wu also mentioned, PDRN injections into the PIH marks will also speed up the recovery.