Red spot where dark colors should be

Today I noticed that my new iPhone 7 Plus has a red splotch when dark colors are shown on the screen. Does anyone know what could have caused this? I have not dropped the phone, nor has there been any unnecessary stress put on the screen. I have Apple Care and am planning on taking it in when I can find the time, but I'm curious if anyone knows what this is, and what Apple might do to fix the problem?