Shell swap's followed by screen issues! Heeelp!

Okay, so yesterday I finally received an after market DSi shell I've been waiting on and performed a shell swap for the first time. Besides audio not working (my fault, was too rough with the wire I think), it worked perfectly fine, functioning like normal. Tonight however, it suddenly started acting weird. I use a great deal of homebrew and have never had issue with it, but while trying to read on my DSi, the screens began to degrade in quality, words becoming illegible due to weird x's throughout them. Now, not only has visual quality itself degraded, but now the top screen is terribly discolored, seemingly with no clear color in particular but leaving my screen either looking like it has a negative colors filter on it or just looking deep fried like the memes. Pictures have been attached.

I have a few ideas of the cause in mind, but I don't know the true problem. For one, it's an aftermarket shell as I mentioned before, and it's not the greatest quality (shell itself doesn't click shut like it should, battery cover can't screw in, etc.) so I wonder if something like dust could've slipped in through a crack in the shell. Next, the infuriating ribbon cables. I did my best to be as careful as possible with them, and while i never saw any sort of tears it did get a wee bit crinkled in the process, so idk just how fragile they are. Third, simply age. I just turned 21 last month and I've had this dsi since i was a little kid, so god knows it could just come down to it's age catching up to it with poor timing.

If there's anybody here who has experience with DSi systems, please respond. I'm trying really hard to not say I'm scared, but my DSi means a lot to me and I'm desperate to do whatever I need to do to rectify whatever mistake(s) I may have made! Please!