iPhone 5s Horizontal Lines

Hello! I have an iPhone 5s and I never remove it from its case (which is an otterbox defender). It slipped from my hands and fell on the ground. The screen is not cracked and there are no damages to the phone aside from horizontal lines that appear near the bottom (image included while phone is still inside the case) of the display screen. I have done a hard re-set, checked to see if apps were causing the problem, and I have concluded its not a software issue since the lines are still visible. Could somebody teach me how I can fix this issue? Thank you so much in advance and looking forward to some help!