What Treatment to Use to Reduce Light Pale Skin to a 3 Year Old Baby Caused by a Second Degree Burn by Liquid?

Hi, my son is 3 yrs.old and nine months ago he suffered a liquid burn on his forehead at age 2. Burn was treated properly by doctor and no there was infection. Doctor said he did not think it will leave a scar just to give it time. I am now worried and seeking help on what I can do in order to help my son because the skin is a little bit lighter in color than his natural skin color which is lighter than tan. Is there anything I can do to help him obtain his natural skin color on the burn?