What is the full model number of the laptop as shown on the information label on the bottom of the laptop?
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
First do not try to charge or to turn on your laptop and then remove the battery as soon as possible from the laptop to minimize any further damage.
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.
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 there is corrosion. The ends of any flex cables and their connectors need to be cleaned as well
Hopefully after you have done all this the laptop might possibly work correctly again.
Here’s a link to the available ifixit HP x360 repair guides that may help if your model is amongst those listed that is
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.