IPhone 5S screen popping out?

IPhone 5s screen popping out?
My iPhone 5s, the screen is slightly popped out. On one side, when you push down with your finger it goes in then goes back out. It isn't very big, just a little, but could it be bad? And have problems a bit later? The phone is less then a year old, should I take it to apple? I still have it under warranty?

If it's still under warranty. Take it to Apple