How can I change my diet to decrease my acne?

Sugar. Gram proactive bacteria love surgery. The most commen bacteria seen in acne fall in this category. Reducing the simple sugars, high fructose corn syrup is a great way to start.
Vitamins A,C,D,E. Eat foods and take vitamins and supplements with zinc, nicotinamide, vitamins a, c, d, e. Eat more fish to get omega acids. Reduce sugar intake and dairy products.