Just to add on a point, there are other skin conditions that may look like acne. A common example is pityrosporum folliculitis. This is caused by an yeast infection and is commonly seen in those who exercise or sweat alot.
This condition commonly affects the chest, back, shoulder but the face is spared. The treatment of this condition is different from acne. Hence it is best to get evaluated by your doctor first to establish the correct diagnosis.