Having a look at your photo, this doesn't seem like display damage, which is good. But something is clearly not working. I have a couple of thoughts, but based on your description that you have replaced the battery, I might hazard that something around the display connector got nudged during the repair.
I would make certain the cables are connected soundly, if that still doesn't fix it, do a careful inspection of your work. You can peel up the sticker around the display connector to make sure everything looks normal
Of the two connectors that come from the display, the one in question is the one closer to the bottom edge of the board.