Green lines on iPhone XR screen

hi!

I fell asleep with my phone on the app Tiktok, I woke up with my phone still playing and it had overheated and it had colored lines, mostly green through the screen and what looked like the page embedded in my phone. I reset all my settings and it went away some. But now they only appear a little bit get worse with dark screens. (Ex: I get on Netflix and the lines get darker).I’ve never dropped my phone in water, I’ve had it since July 2021, never had problems until today.