Day 5 Of fading your Melasma Now we are finally at the step of exfoliation in the exfoliation nights. Please make sure that you are using an AHA exfoliant that matches your skin type and your skin sensitivity level. Sensitive skin can opt for Mandelic acid serum or a PHAToner Dry skin can opt for Lactic acid serum, start with a 5% concentration and in a few months graduate to 10% Normal to combination skin can opt for glycolic acid. Here again first time users must start with a 5% concentration