IPhone display not working properly after disassembling?

I disassembled and reassembled my iPhone 4 to try to fix a problem with the audio compiler (for the last two weeks, no one can hear me on calls) with a fix I found online to secure the connection. I followed a video tutorial for disassembling and reassembling. The first time I turned it back on, the screen was really faint and shaky, but I could still see the apple logo and icons. I disassembled again and reassembled to check all the connections.

The second time I turned it back on the screen is just blue with lines. What did I do? I have checked the connections again and they seem to be fine. I'm going to lose my mind, now my phone is completely unusable. Please don't say "take it to a repair shop like you should have done in the first place." I can barely afford groceries, this phone was a gift I certainly couldn't have afforded. I do not have a back up phone that will fit my sim card.

Any ideas about what is wrong and what can be done to fix it will be appreciated more than you know.

You must have put the digitizer in direct sun light. No fix.