Oil under screen of IPhone 6s.

I put iPhone 6s in my bag not knowing that my sunflower oil from my food tech ingredients had leaked all over my bag. It must have been in the bag for about 10-15 minutes before I realised the situation. Me and my friend immediately wiped the phone clean and made sure it was working. Everything was working perfectly fine however I noticed a brightened area at the top left of my screen and throughout the day spread to about 3/4 down my screen. I am currently trying the rice technique however do you think this is irrepairable or is there any way this can be fixed? Thank you x