[] try putting it in a dry box w/ the battery removed for a couple of days (Airtight box with a dehumidifier or two. ).
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[] It would be better if you have a hygrometer which will tell you if the air inside the dry box is dry enough - meaning the device is no longer wet- but it's not needed.
after 2 days, turn it on and see if it goes back to normal. Otherwise, it's likely fried then back up your files and bring it to a service center.