iPad 4 Repair Gone Wrong?

I recently dropped my iPad 4th Generation on the ground and cracked the front. I went to repair it myself because 300-350 dollars which is WAY to expensive to replace a screen. When I finished my repair and closed the iPad, there was a dark dim on one side of the iPad and the other side is completely fine. The picture below shows a perfect example, one side is bright, the other is dimmed. BTW, it may seem like it was a bad picture, but I can assure you, it is actually very accurate of what is happening. I was wondering if anyone could help me. Did I miss a step? Please don't tell me to "get it fixed" because it cost more than a regular iPad which, I'm guessing, is pretty expensive in general to any average consumer, like me. Thank you!