Having acne is rarely a result of an under washed face. In fact, many people with acne actually over-wash their face. Sometimes washing your face too much can make things worse. If you scrub too hard, you could aggravate your acne. Also, certain alcohol-based astringents could be drying your skin too much. With that being said, washing your face with water and a gentle cleanser every night is beneficial. However, most cases of acne require more than just keeping your face clean.