Possible battery bulge with screen light spots

So for the background: I realized my battery was on its last legs around christmas. I bought a battery replacement kit from here on 1/6/2018 and the whole process was super smooth. My battery life was back to something respectable and no issues.

Until about a week ago.

I started to notice a light spot toward the top of my screen (i'll attach pictures). It started to grow and is now a 'band' of what appear to be LEDs. I noticed that early on they would disappear if pressure was applied around the case...making me feel like this was a physical problem. I then noticed that my battery life was significantly diminished...i mean dramatically. I was getting through most of the day on a single charge, but now i'm lucky if my phone is alive by the time i get off the train in the morning.

Now, a week later, the band of lights is incredibly noticeable and the screen appears to be bulging away from the case itself.

Is this simply a matter of getting a new battery? I am only 4 months into the ifixit replacement battery and despite my previous experience with the dead battery from Apple, i never saw anything like this.

EDIT: Also secondary question...if this battery is faulty and causing this sort of expansion, is it possible that my screen is permanently damaged?