Wet paper is the worst because it never dries flat again. Mine went through the wash once and the pages turned into a crinkly mess, so I started using a pencil to mark things and it actually held up fine. What saved me was sticking a piece of washi tape on the spine afterward to keep the pages from tearing when I flip through fast. If yours only got a little damp, try pressing it under a stack of heavy books for a day or two before you write in it. A cheap fix that worked for me was just switching to mechanical pencils since they don't smear when the paper still has a bit of moisture. Honestly the notebook ended up with more character that way.