Irritated part of my skin from benzoyl.p still appears darker and red from surrounding healthy skin even after a year. will it ever heal and even out?

Hard to say: Inflammation of the skin from irritants can cause darkening/spotting which can be permanent in some cases. There are many over the counter skin lightening products but none is guaranteed. Sometimes a trial of 0.5% or 1% hydrocortisone cream (very sparingly 1-2x/day) for a few weeks can help lighten these, but a dermatologist may be able to offer other options