See this page: https://www.ifixit.com/Wiki/Electronics_Water_Damage
Leave the pen/tablet to draw dry for at least 48 hours. Keeping it in a dry warm (but not hot) place will help.
if your tablet is connected with any cables, disconnect the cables.
If your tablet is connected wirelessly, it may have an on/off button. Turn it off.
Remove the nib to help it dry faster
Keep the pen upright with the nib removed and pointed down to help drain water
Some pens buttons are a "rocker" type which can be removed and put back in. if you are confident you won't harm your pen this is one option.
Some people, disassemble their pens - but only try this if you find a good reference on YouTube and are confident around electronics.
https://www.reddit.com/r/wacom/comments/tcmqpz/ctl4100_wacom_intuos_pen_accident_with_water/ -