How Can I Reverse the Damaged from Salicylic Peel?

It is very common for the area peeled to get darker before it lightens the area. Please avoid direct sun exposure and wear sunscreen to prevent post-inflammatory hyperpigmentation. A good protocol is to pretreat the area with skin lighteners PRIOR to peeling to reduce PIH, but I would not call it PIH until it lasts longer than 10 days. Your dermatologist can treat PIH early, so be sure to get a follow up in 7-14 days post peel. FYI, in general, I prefer global to spot peeling for acne and its residual discolorations.

you will need to see your dermatologist to help lighten this skin. It looks like you have postinflammatory hyperpigmentation due to sun exposure while in the healing process of your peel. You will likely need bleaching agents and must stay out of the sun.

If you are using a peel pad that is twenty percent salicylic acid, that is too strong for everyday use.  See your dermatologiist who can prescribe you a topical medication to help with healing and stay out the sun completely until this problem is resolved.