Exfoliating is a popular way to relieve bacne, but it's also a preventative measure as well because it sloughs off dead cells and makes room for healthy, strong skin. This should be a biweekly practice because exfoliating too often can irritate the skin.
Since back skin isn't usually as sensitive as what's on your face, treat yourself to a hearty body scrub like Odylique Cotton Candy Body Scrub (£25) to slough off dead skin and debris. This exfoliator is great for dry or sensitive skin.