Iphone 6 problems with screen

Hi I have an iPhone 6 and the screen is actually slowly popping off, its never been dropped and has lived in a lifeproof case since I have bought the phone a year and a half ago. My battery isn't holding charge very long and I am worried its something to do with the battery. It almost seems like the battery is expanding I am a little worried about it. Just wondering what I should do with the phone or if apple can replace it. Its a huge malfunction of some sort I had my iPhone 5s for over 3 years and no issues. Thanks