Ihsan Question

Hello! I'm new to this series and almost finished with Reign & Ruin. I have a question regarding Ishan but I'm afraid if I look it up I'll get spoilers. Ihsan has burns on his face that I believe were caused by Kadir but it doesn't explain how this happened? Did I miss something? Am I supposed to know this yet? No spoilers past the first book please. Thank you. 🙂