Welp... I would recommend opening it up... try to leave it open to dry out fully... If those batteries inside explode, you won't be happy. Make sure the inside doesn't have any acid (from batteries) on the circut board... and be sure to check the batteries too.
Many people recommend placing the tama in a bowl of uncooked rice... That should help take the water out of the tama. A Hairdryer helps, but make sure not to point it in one spot for too long... Let the tama dry otherwise.
Your purse... Make sure you wash that well... School Toilets tend not to be too clean.... Maybe add a little extra of detergent/cleaner......
You will know if your tama isn't working right... Slow, Part of the image is gone, not moving....etc. Stuff like that.