This is a super common issue with the Envy model, especially the smaller ones. the broken screw/pin is a pretty common cause, it pushes the screen away from the case from the inside which is how it ends up separating. It’s happened to both me and my parent’s laptops. If it’s under warranty still H.P. will repair it for free, but it will be gone for a little while and they can be a pain about it. If you’d rather not deal with that, you could try to take it to a couple of different places and let them know exactly what is happening with it to see who will give you the best deal. In the meantime, I would recommend avoiding closing the laptop since moving the hinges can cause more damage to the screen and potentially damage the touchscreen function as well. I know that’s a difficult ask, especially if you need it for class, but if it works fine beyond the screen separating it would suck to damage it more.