IPhone X screen flickering and lines

It was working perfectly and then one day it just started showing lines on the screen both horizontal and parallel. It is not as visible when the screen is on full brightness but as it fades to turn off or if the brightness is turned down the lines become more visible sometimes to the point of not being able to read the screen. It seems to happen more often when the phone is getting heavy use vs days when I just answer a few messages. This phone has not had any repairs, replacement parts nor has it been dropped hard and it is in a protective case (otterbox defender). I did a hard reset and it’s still there. Also, I live in Costa Rica where there’s not a genius bar or a nearby apple store.