Green line on screen after cleaning up and thermal paste replacement

Hello there, I &&^&@@ up pretty bad with my phone, so I was having problems with my SIM cards, so I thought why not clean up the slot? I did it and I fixed the problem but I created a worst one.

After I cleaned up with q-tip and toothpick all the dirt inside that part I pointed out with red arrow https://i.imgur.com/3GGkOWr.png (below that piece, inside) my phone got a green line just like this one https://i.imgur.com/aXoRWMO.png

I only cleaned it up without removing that piece, I cleaned up the dirt inside it (there was a lot, infact I had to use 5-6 q-tip), I used isopropyl alcohol (the one used for electronics).

And, not only this, now, I may have also removed thermal paste with the q-tip without realizing it, I didn’t know there was thermal paste in the phones, I’m a beginner.

So, how can I fix it? Should I disassemble and clean up? And put some thermal paste again? I have some Arctic Silver 5 (the silver one)

Sorry for the long post, I really hope you guys can help, thanks.