Hard to say what might have gone wrong; take it from me, there are a lot of ways to mess up when working on a cell phone; I should know, I've probably done most of them.
I'd suggest starting out with rechecking your work; open it up again and unplug all the connectors you removed and check them with a magnifying glass looking for any bent or broken pins on both sides. Examine the logic board for any place where a component might have been knocked off either next to the connectors or anywhere that might have been touched if you had to pry the board out of the phone.
Check the flex cables for any sign of damage as well. Clean all the connectors with 90% or higher concentration of isopropyl (rubbing) alcohol then reassemble and see if anything has changed.
Give that a try then come on back and let us know if you find anything and what happens when you plug it all back in and try it. If you can get some high resolution pictures of your logic board we'll be glad to take a look and see if we can spot anything.
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