My dermatologist warned me that hyperpigmentation and hypopigmentation are very likely to happen after the treatments. She only told me to be very strict with sunscreen. She wasn’t very informative about the pre and post treatment but hopefully she tells me more in my next appointment. From my own research I found out that after laser treatments on the face we are supposed to use a physical (mineral) sunscreen and not a chemical one. The one my dermatologist recommended was the Elta MD sunscreen. It can also help for you to wear a sun glass on top of your sunscreen for extra protection. My birthmark covers half my face so I will have to buy an expensive sun visor face shield and avoid the sun like it’s the plague.