Nintendo DSI?

I repaired the L and R buttons on my Nintendo dsi that were no longer working with contact spray. Now the upper picture is somehow streaked, so only minimally, you hardly notice it and it flickers slightly and the screen is much brighter. Could it be that I made any contact when opening the device, or is it the flex cable. Does anyone know about it and could tell me how to fix it?

I don't know about these things. Does it have an LCD screen? Then you have probably shifted the rubber lips or introduced impurities into the contact surfaces. So far I have caused more damage than improvements made by these interventions. In other words, my success rate was around 20%.