Hardware Misc DSi shoulder/trigger and screen issue

[NotLuzeria]

My childhood DSi has had it's L/R buttons not work (or at least rarely work) for a while now, and I ignored it since I have a N3DS to play on instead. But I wanted to fix it since I could use it for local co-op on NDS(i) games with friends.
So I tried the usual, assuming there was dust between the actual switch and the physical shell, trying to blow it out but it didn't work.
I opened it up to check underneath to see if anything was blocking it and nope, I can't see anything.

But when I put it back together, the screens had this wavy almost VHS filter effect, and if I push the DSi REALLY hard together, it kinda goes away a little?
I've attached some images I took while I had it opened, let me know if you need me to photograph any other part more clearly!

 

[Maxwellp]

You need to readjust the potentiometers for the screens. These are small, round holes attached to the trigger ribbon cable. You can fit a screwdriver in one and gently turn until the screen looks better.

Look up an image or video of the process. It's very easy once you know how to do it but you have to be careful not to damage them.