I forgot to close the backseat window last night，and it was raining. so the back seat was wet by the rain. i used the cloth and paper towel to wipe it off, but it is still wet inside. is it going to be mouldy or a big problem to my back seat.

 

If you live in a warm climate, you can leave the windows open during the day and let the seats dry out. I have used this product in Florida for removing the moisture in condominium closets and storage rooms:

http://www.damprid.com

They sell it at Home Depots.

 

if you really wanted to get down to it

remove seat
remove covers
remove foam and wash in utility tub full of water with a cup of bleach
squeeze dry
let sit out to dry
wipe down leather with cleaner
let dry
reinstall foam to seats
reinstall seat covers
reinstall seat