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 has been properly cleaned away
First do not try to charge or to turn on your laptop and then you need to disconnect the battery as soon as possible to prevent any further damage.
After this dis-assemble the rest of the laptop and clean all the affected parts using Isopropyl Alcohol 99%+ (available from electronics parts stores) to remove all traces of corrosion and water. If possible, do not use "rubbing alcohol" as in some cases this is <70% IPA, 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 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 boards. Disconnect any flex cables and clean the ends of the cables and the connectors as well.
Hopefully after you have done all this the laptop might possibly work correctly again.
Here is a link to the ifixit Acer Nitro 5 AN515-53-55G9 repair guide which may be of some help.
If this process seems too daunting, take your laptop to a reputable, professional laptop repair service, experienced in water damage repair and ask for a quote for a repair. If you decide to do this, do it sooner than later.
It looks OK but zooming in I think that I can see where it might have been wet. I may be wrong but I think that you can see the discolouration that has occurred due to the water. You may just want to go over the areas indicated and do a final check. Moreso where there are components rather than just plastic covers etc.
Here’s a zoomed in image of your image showing what I mean. The arrows are only to show the general areas and not to pinpoint exact spots
(click on image to enlarge for better viewing)
What does the underside of the keyboard look like?
Looks like that you may have been lucky ;-)