Definitely let it dry out if it’s damp.
Take it all apart and wipe out any mildew/mold with paper towels.
Be careful when touching the power supply!
Next use an old tooth brush and gently brush off the motherboard.
If you are getting error 7 the cable could be loose or the hard drive could be totally dead.
If it’s dead there is not much you can do. The drives are paired to the console and the only way to swap in/pair a new drive requires the old one to be still working.