I am using epiduo on my face and back and I was cleansing with aftican black soap now I have a big itchy dark spot on multiple spots on my back... What could it be? And what type of soap could I use best with the epiduo for my body acne?

Post inflammatory. Post inflammatory hyperpigmentation is a common and normal response during the healing process. When traumatized skin heals, redness, followed by dark discoloration often occurs. With time, the site will usually resume normal coloration to match the surrounding skin. Hypoallergenic noncomedogenic soaps and moisturizers may help (check the sensitive skin section of the pharmacy).