Before setting out to apply calamine lotion, it is very important that you clean the affected area thoroughly. For this, wash the area with a mild soap or a herbal soap, which is well suited for an acne prone skin. If the acne scars are on the face, remember to remove the makeup thoroughly as well. If any trace of makeup, oil or dirt is left on the skin, then application of calamine lotion on the skin might not prove to be so effective. Also, wash the affected skin gently as acne prone skin is often sensitive, and hence, should not be rubbed or handled in a rough manner.