Hi @samwill ,
Do not attempt to charge or to turn on the laptop and then disconnect the battery from the laptop to minimize any further damage from occurring.
The impurities in the water causes corrosion and provides circuit paths for the electricity which were not in the laptop’s operating design and could damage the components. The corrosion starts immediately and is ongoing until it is completely cleaned away.
Then you need to dis-assemble the rest of the laptop and clean all the affected parts using Isopropyl Alcohol 99%+ (available at electronics parts stores) to remove all traces of corrosion and water. If possible, do not use "rubbing alcohol" as in some cases this is only 70% IPA or less, can contain additives 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 the process. 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 the shields that may be covering some components as the water may have got in under them and corrosion is occurring there as well. The ends of any flex cables and their connectors need to be cleaned also.
Hopefully after you have done all this the laptop might possibly work correctly again.
Here is a link to a video that shows a motherboard replacement for the laptop which may be of some help. It shows how to open the laptop and to disconnect and remove the battery as well as getting access to the motherboard so that it can be inspected and properly cleaned.
If this process seems too daunting, take your laptop to a reputable, professional laptop repair service, experienced in liquid damage repair and ask for a quote for a repair. If you decide to do this, do it sooner than later. It isn’t going to fix itself.