I have caucasian light skin, with burns from IPL. I had dark brown scars in this area! How long will they take to go away?

I am a 31 y.o I've been seen by a nurse not a doctor and I asked her if its helpful to do IPL for Keratosis Pilaris dark spots and pigments at my buttocks area and behind and in between thighs and she said yes of ofcourse! So, I had an IPL treatment 19 days ago at (Laser Away) in San Francisco. Burns all over the area. Their office didn't respond. A dermatologist prescribed Neosporin_Hydrocortisone. What to do for Hyperpigmentation after flakes?