iPhone se turned black, force restart isn't working. What do I do?

My iphone SE (2020) is not working. This has happened once before. The screen has just completely turned black but all the functions are working, it's just the screen that is black. I have tried the force restart multiple times but it hasn't worked. I've contacted people to try to get this to work, we have tried multiple methods but nothing seems to work. I've already scheduled an appointment to bring my phone in this friday, I want to know if there is anything else I can try before bringing it in. Please help!!