Yellow Screen on IPhone 13 Pro Max

I bought my iPhone 13 pro max from Apple refurbished online store (Italy) barely a month ago. I brought the phone out of my pocket this afternoon to discover yellow screen with flash lights. I'm so scared right now!

I managed to power it off, left it for a few minutes before turning it on again. Normal screen has been restored now, but I'm dead scared! Is there something I need to worry about?