Jackie Silver shows you how you can use lemon to treat acne. Follow these quick steps to start treating your acne with lemon: You will need a lemon, a sharp knife, spring water, cotton balls and a small bowl. Roll the lemon on the counter to mix the juice and make it easier to cut, and then cut it in half. Add the juice to the spring water. Dip the cotton ball in the lemon water and dab onto your skin. Cover and refrigerate the diluted juice.