How to get rid of water blotches in the corner screen

hi!!

so i accidentally had a water bottle spill inside my backpack and realized about 5 mins later, but the left side of my 2018 macbook pro got the most damage from it leaving a water blotch looking stain and i brought it to my school’s tech people and they opened it up and let it dry for about 4 days and when i got it back- it was way better than before but there was still a small stain in the corner. I was wondering if anyone had any solutions for this, whether i can put it in front of a fan for a couple weeks or if there’s literally anything i can do to fix it.

thank you all for any help!!!