Camera issues after screen replacement

So, a While ago I replaced my phone's screen which was blacked out due to water damage. At one point I had it all reassembled and booting except I couldn't put the back cover on it because the power button assembly was messed up during my initial tear down. However when the phone turned on the cameras worked. Later I went back and replaced that, but now the cameras don't work. It's been like this a while and I've basically given up on getting either camera to work again. In apps that use the camera they are either black or show an undescriptive error without a code and crash. However, twice, rather recently, the front facing camera (selfie cam) has flickered into existance again. I was using Snapchat when suddenly to my shock the camera was working again. The picture was blurry and kinda hazy with vertical lines, and the back facing camera still didn't work at all. Then it stopped working again shortly after. This happened a second time today, and then stopped working again. This makes me think something could be loose, but as far as I can tell without a complete teardown of the whole phone no ribbon/flat cables are loose. Any ideas? Is it just fried?