What Causes Burning In The Lower Back During Laser Treatment?

I got laser hair removal done for my back about 10 hours ago. During the procedure i experienced slight burning on my lower back. By the time the procedure was over, i had few burn marks on the lower back. An ice pack was immediately applied to the affected area. The doctor has asked me to apply flutibact over the burns for next few days. Is it normal to get laser burns? i don't have burns over the rest of the back, only a small patch on the left side.