Stripes on iPhone screen after I replaced the screen.

Help!

As a beginner, I tried to replace my screen after i smashed it. I have put everything back together and now when i turn it on, funny lines come up on the screen, everything looks very white and washed out and there is a flicker on the right hand side of the screen. When i first fit it about a day ago, it was fine and everything worked perfectly but i turned it off and back on again and then this happened. Could anybody help me out - has anyone come across this before?

Thank you