two white dots on the top left corner

Is it still there when you change the back ground?

I suppose it isn't superficial and can't be cleaned off?

I suspect however that it was pressured in those two spots killing the led pixels there.

If it's still under warranty take it in for a repair at an Apple Store. If you are not near an Apple Store you can send it in for repair. Any warranty issues should be covered at not cost to you (other than shipping fees). However, if you are no longer under warranty then you can have the touch screen replaced by yourself or a 3rd party. Hope this helps!

It’s not screen or pixels. Shows only on home screen and not when u use apps.

I just the same issue with the iPhone X, I just re-started the phone and now they are gone! (press the low volume + Power Button) - hard power off.

I have an iPhone 6s Plus and just had the exact problem… Read about kikexxx69’s answer and did the same and the dots are gone

It’s the start/stop dots when you select text on the iDevice.

They get stuck on screen for some reason

Power off /on will fix it