Hello, Welcome and thanks for posting your query to HCM. After reading your query it appears that you have the problem of “post-inflammatory hyperpigmentation” which we commonly call as “PIH”. This is a common phenomenon occurring due to the over stimulation of color giving cells known as melanocytes. In certain situations, where there is some inflammation is present due to application of some irritant material or chemical then that area heals with this phenomenon of PIH. Here in these situations these melanocytes produce more color due to the continuous stimulus of that inflammation. In your case as you applied more of the gel which caused burn on face and later on to PIH. Your doctor has rightly prescribed you the cream as it is well known lightening agent, but is to be used for short period of time and only in guidance of your dermatologist. For the rest of the advice the most important thing is sun protection. It is good that you are already using sunscreen. Use it multiple time in day especially half an hour before going out and then replication after 3 hours. If you can use some physical barrier such as calamine lotion over the affected area then also be of useful. Rest do not try any self medications as it can aggravate the situation. The mark takes some of months to get reduced and then vanishes in next couple of months so have patience for the same. Hope it helps. with good health wishes, Dr Sanjay K Kanodia D ( Dermatology)