Tiny spots on glass
I've had my iPhone 6 Plus for about a month and I now notice a couple of tiny spots (about 1mm across) on the glass towards the top of the screen. I'm pretty sure these were not there when I bought it, so they must be due to wear and tear (just carrying it in my pocket).
I have tried glass cleaner, rubbing with a micro fiver cloth, etc. They don't seem to be scratches, but rather places of less shine than the rest of the screen (abrasion?) Perhaps these are places where the oleophobic coating rubbed off? I have the iPhone in a case, but the case covers only the back.
The spots are not major, and they are not directly over the image area of the phone, but I worry that this kind of damage could spread.
Is this kind of problem common? Should I purchase a case that covers the front as well as the back (as far as I know, Apple's own cases do not). Is there a way to fix this damage? I had my iPod touch for 7 years of regular use, and the screen of that device is still in pristine condition.
iPhone 6 Plus, iOS 8.2, 128 GB