Charging your device while the usb port is still wet may damage the charging board, and this is what I think it happened.
As stated many times, no warranty will cover user damages (yes it is, in the end).
I suggest to open it and replace the charging board. You can find it here:https://m.it.aliexpress.com/wholesale/B ... ging-board
If you can't replace it, I suggest to take your phone and new charging board to the nearest 3rd party phone repair shop to get the work done.
I also suggest to check for a correct seal made by screws' o-ring:viewtopic.php?f=191&t=348815