As you know water, and electronics and electricity are not a good mix.
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 is ongoing and doesn’t stop until it has been cleaned away.
First do not turn on your laptop and then you need to 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. Do not use "rubbing alcohol" as in some cases this is only 70% IPA or less, can contain scents or other additives and is not as effective. If you do 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 PCBs be gentle when handling and especially when brushing away the corrosion. You do not want to remove any components from the board.
Hopefully after you have done all this the laptop might possibly work correctly again.
You may have to replace the keyboard as you can cause more problems than what you had trying to repair it.
Here is a link to the ifixit HP Spectre 13-4003dx x360 Repair guide which may be of some help.
Here’s a link to the HP maintenance and service guide for the laptop, which will also help as it contains all the part numbers for the various parts in the laptop in case you need to replace any parts e.g. p.43 has all part numbers for the various keyboard(s) available for the model.
If you do have to replace any parts, just search online using the part number only to get results for suppliers of the part
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.