Replenix Gly-Sal 10-2 Spray "For the stubborn back acne — or "backne" — I recommend glycolic acid sprays, as it can be really hard to reach those areas. Replenix sells a great Gly-Sal 10-2 Spray (£18) , but most of them at the drugstore are equally effective." — Dr. Valentin Image Source: lookfantastic.com Gly-Sal 10-2 Spray £18 from lookfantastic.com Buy Now