Bad battery draining, and overheating?

So I have a long, taxing, and interesting repair history with my iPhone SE. First, the screen was broken when I bought it used, so I replaced it with some random screen from amazon (which was my first problem). A little while after I replaced the screen, I discovered that the camera and the flash didn’t work. So back I was taking that phone apart. I unplugged the screen and then reconnected the camera but then all my troubles fell upon me. When I plugged the screen back in it got all fuzzy. It cleared up a little, but it still has periodic scan lines and colored noise. So I ordered a new screen, and put the phone back together. The camera and flash do work now. But things didn’t end there though, while I’ve been waiting for my new screen, I've discovered that the battery drains WAY faster than it used to, around 2-3x faster. I could be hypersensitive, but I have also noticed that the phone gets hotter quicker around where the screen connects to the logic board.

So that is my current state of affairs, and it is really perplexing. I have looked around this site for similar problems, but all the answers are really confusing. Hope someone can help!