@angelsalas skip the rice. Using rice is about the same as doing nothing, it does not do anything. All it does is waste valuable time that you could have spend to properly decontaminate your phone!
The very first thing you want to do is to not try to restart/sync the phone. This may further damage your phone. The next thing to do is to clean it. Disassemble your phone using iPhone XS Repair these guides. Clean everything with +90% (no less than 90%) isopropyl alcohol. Follow this guide, and even so it was written for a 3G, all the points are still pertinent to your phone. Pay particular attention to the SMD components, check for charred missing or broken components. After a proper cleaning you can then dry the board in an oven or equivalent at 220deg F (not higher;-) for a few hours. Best way to clean it would of course be through an ultrasonic cleaner. Consider professional help with that When it is properly cleaned, replace the battery. All these steps are to avoid delayed failure caused by corrosion. Once all this is done, reassemble your phone and reevaluate. Water damage is the most difficult pair. Any part may have failed and it will require a lot of work and troubleshooting. Even with all of this there is still a chance that your phone will never work again. A good microsolder specialist would be the person that can decontaminate the board properly as well as assist you with any repairs. Right now, everything will only be a guess, and the longer you wait the more corroded it will get. Hope this helps, good luck