Why is touchscreen unresponsive after use in pool (Water resistant ph)

I can use volume buttons, Google Assistant, and fingerprint sensor to control the phone but not touchscreen. (Screen has slight cracks but none big enough that would let water into the phone)

I was using my phone in the pool (1m deep) today for taking photos and videos for about 30-40 minutes.

The Galaxy S8 and S8+ feature IP68-rated water and dust resistance. The IP68 rating indicates that the Galaxy S8 and S8+ is water resistant up to 1.5 meters (4.92 feet) for 30 minutes. - Forbes

It would’ve been submerged underwater for about a total of 5 minutes out of 30-40 while the rest of the time it would have been wet, but out in the open.

The touchscreen later become unresponsive, so I decided to remove the tempered glass as I thought the water may somehow by between that and the phone glass.

I was charging the phone but I read somewhere that you should not be charging it

No luck, so I put my phone in a bag of rice. Kept checking every 2 hours or so until 7 hours later it was finally working normally.

Then after a few minutes, the touchscreen again stopped working. I charged my phone. I can do practically nothing, but all its software features are running in background. e.g. I am using WhatsApp Web.

I would prefer not going to a repair shop to prevent my parents from finding out about it, unless that would happen to be the last resort. It worked for a bit in between, so it could probably work again.