Mederma Scar Gel is clinically shown to improve the color, texture, and overall appearance of scars.It works for many types of scars, including acne scars, surgery scars, and scars from burns, cuts, and other injuries. You can start using Mederma gel as soon as new skin has formed, typically two or more weeks after the injury or surgery. Make sure the scab has come off naturally and any stitches have been removed. On older scars you may start using Mederma immediately.