“Backne” is street slang for back acne. And while the contraction’s definite origin is unknown, it can be said that it comes from the fact that nearly everyone in the world has, at one point in his or her life, experienced having back acne. Indeed, back acne is universal enough to merit its own term.Back acne knows no specific target. It afflicts people from ages ten to forty; sometimes even years after that. A lot of theories have been introduced as to why back acne happens. Sadly, however, non.