Estelin Salicylic Acid Serum Pore Refining improve aging,balance oil secretion, tighten and refine pores, better skin texture and enhance skin fineness. best treatments for acne scars and marks. It is an excellent exfoliant that helps to remove acne-causing bacteria, slough dead skin cells and fade dark spots or marks. In addition, it evens the skin tone and treats skin discoloration.