@sammi1234 it has the potential to get worse once corrosion sets in. for now it appears your Switch has already trouble with the battery and its circuitry (Possibly the USB-C port). I suggest that for now you stop continuing to try to charge, sync or otherwise use the Switch. This potentially can make a bad situation worse.This may further damage your game console. The longer you wait and the more of the water evaporate, leaving substances behind, the greater the chance of terminal failure.

The next thing to do is to clean it. Disassemble your Switch by using [these guides] . You must remove all EMI shields from the motherboard. If you do not remove those, you might as well not do anything. After you removed those, clean the whole board, connectors and all with +90% isopropyl alcohol. Follow this guide , and even so it was written for an Apple iPhone all the points are still pertinent to your console. While you clean your board, check for any obvious damage, like burned or missing components etc. When it is properly cleaned, replace the battery. All these steps are to avoid delayed failure caused by corrosion. Best thing to do, would be to clean it with an ultrasonic cleaner, but if you do not have access to one, this will at least help. Once all this is done, reassemble your Switch and then re-evaluate. Until it is cleaned, everything will only be a guess. Just always keep in mind, that even with all this, water damage has only a small chance to be fully repaired, but you should at least give it a try.