Red crack fading into blue on my iPhone 6

Help. I'm so confused as to what this may be and if it can be fixed at all. My iPhone 6 has two very light cracks running diagonally across my screen and is crackers more in the upper right corner, it's hardly noticeable and I don't mind it. But two days ago, my phone fell out of my pocket and I wasn't too concerned about it, but when I looked, there was a short blue line (crack like not straight) running slightly diagonally under (not on) my screen for maybe two to three inches. I didn't mind it at first since it was hardly noticeable, but the next day I awoke to find black lines forming on either sides of the small crack that appears to be under the screen, not a normal one. Slightly more concerned, I left it be. The next day, there was a larger clump of them in the corner covering the very edge of my battery percentage icon, and just today it has begun to glow a vibrant red at the very top and the lines are getting more plentiful. I am very concerned that this could be either dangerous, or simply something I will need to pay to fix. If anyone can help me, please do.