How to Lighten the Hyperpigmentation on my Face Caused by Burn 20 Years Ago? (photo)

I had burn on my face caused by candles 20 years ago. Now my face is darker on one side and it lowers my self esteem, self confidence, especially when people talked about my face. This definitely affects my social life and employment opportunities. Is there anything that I can do to lighten it to make it look normal besides the skin grafting? any gel/cream that I can use? or any natural product that can help reduce?Attached is the pic of my face. Thanks