Iphone 12 screen patch

I've noticed a small white patch on the left top corner of my phone yesterday , I assumed it's an air bubble between the phone screen and the screen protector. Today the patch has evolved to thin discolored line/area and now it's about 4 inches long. Visible when the screen is dark. I didn't drop the phone, not exposed to water, only 8 months old, no visible cracks or damages to the phone. I suspect it's something to do with the OLED screen, is it possible OLED to get damage without any external damage?