The damage is done and can get worse as more time goes on. Turn off the Laptop and do not use. Contact your local Apple Store and get an appointment scheduled ASAP if you do not have an Apple Store near you contact Apple Support.
- What should I do if I spilled water on my MacBook?
- Safely disconnect your MacBook from power.
- Move your MacBook to a dry space.
- Power off your MacBook immediately.
- Unplug accessories and disconnect the battery.
- Absorb as much liquid as possible.
- Let your MacBook air dry for at least 48 hours.
Get Support – Apple
https://getsupport.apple.com/
Call Customer Support (800) MY–APPLE (800–692–7753)
or online https://getsupport.apple.com/
or call AppleCare Support at 1-800-APLCARE (800-275-2273)
Outside the USA—Contact Apple for support and service by phone
See a list of Apple phone numbers around the world.
https://support.apple.com/en-us/HT201232
Water damage is not covered by the normal warranty but your Applecare Plus will offer reduced cost coverage. Here are the relevant Apple documents with quoted sections:
Liquid damage to iPhone or iPod isn't covered by warranty - http://support.apple.com/HT204104 - "iPhone and most iPod devices are equipped with Liquid Contact Indicators (LCIs) that you can see from the outside."
AppleCare+ for iPhone 11 Pro, iPhone 11 Pro Max, iPhone XS, iPhone XS Max, or iPhone X
"AppleCare+ for iPhone extends your coverage (1) and includes up to two incidents of accidental damage coverage every 24 months. Each incident is subject to a service fee of $29 for screen damage, or $99 for any other damage, plus applicable tax."