Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I advise you to dry out the camera thoroughly first of all, even if it's a waterproof model. After the following guidelines:
First: an electronic device with dampness inside it needs to be kept powered Off, strictly Off, until it is *certain* to be dried. So, remove the battery, and keep it apart for days.
Second: take rice, uncooked rice either brown or white, but hopefully not too chaffy. Blow on it and stir it, to get rid of all fine particles - you don't want them to get into the device.
Third: place that rice in a container, and the device on top of the rice, with the open hatch or battery port (left open if it has a cover) upward out of the rice, and enclose in a watertight container or bag, with lots of loose air trapped in it, and an air bubble above the device.
Fourth: leave undisturbed in a warm place, for days, not just overnight. It must be thoroughly dried to have a chance of being undamaged.
Should the battery (kept apart) be dried too? if it got at all wet, yes, but several days just sitting on a shelf, after wiping the battery terminals dry enough with a clean dry cloth, should do that - the battery is sealed anyway, unless its severely damaged.
Note: Silica gel, warmed to absolute dryness in a warm oven, is ideal. But that much is hard to obtain, and uncooked rice *will* do.
How old is the camera? If less than a year old, if repairs are ultimately required (which if the error codes don't go away, is quite likely), then you will have those repairs covered by Olympus' warranty, hopefully. Let me know, if so, so I may advise you further.
That's about it. Good luck. And please rate my answer, hopefully favorably, so that I may be paid for the work I have done on your case.