Default [Q] display problem

I have an HTC one single SIM version and I'm having a blue tint(as if I touched my screen with the ink of my pen )on my screen and I can make out only when I'm in white background.. I visited HTC service centre last week ,they told my display is bad and they replaced it with a new one ,then suddenly today i saw it back on my screen on the same exact spot ...but it is little less this time ...and I don't no what to do ...and my warranty will expire in few days ..any suggestions ?? ....
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LG COOKIE->MOTOROLA MILESTONE->SAMSUNG GALAXY S->SAMSUNG VIBRANT->SAMSUNG CAPTIVATE->SAMSUNG GALAXY S 4->HTC ONE