Hi @nightbear
Having come into contact with water is not good.
Check the status of the LDI (liquid damage indicator) which can be seen when the battery has been removed from the phone. If it has changed from white to pink/red then this means that water has entered the phone and most likely corrosion has set in
The impurities in the water causes corrosion and provides circuit paths for the electricity which were not in the phone's operating design and could damage the components. The corrosion starts immediately and is ongoing until it is completely cleaned away
It's most probably too late but you can only try the following and check if you can get it working properly again.
For a start, do not try to charge or to turn on your phone and then remove the battery as soon as possible from the phone to minimize any further damage.
Then you need to dis-assemble the rest of the phone and clean all the affected parts using Isopropyl Alcohol 99%+ (available at electronics parts stores) to remove all traces of corrosion. If possible do not use "rubbing alcohol" as in some cases this is only 70% IPA or less, can contain additives which may leave conductive residues and is not as effective. If you do have to use it check the label to verify the amount of IPA. The higher the percentage of IPA the better
Here is a link that describes what happens. Electronics Water Damage
As always with electronics, especially surface mounted pcb be gentle when handling and especially when brushing away the corrosion. You do not want to remove any components from the board. Remove any shields that may be covering some components as the water may have got in under there. The ends of any flex cables and their connectors need to be cleaned as well
Hopefully after you have done all this the phone might possibly work correctly again.
Here is a teardown video that may help
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