Mind of its own!

Hi
My 8820 has a mind of its own!
If I leave it unlocked it will start to write an email then save it to drafts. I have had about 20.
Whatever 'function' i am on, the phone works itself.
I have done many battery pulls, but it still continues.
Any thoughts please?
There is a possibility that it got wet yesterday, in the rain. I have tried drying it today, with the hairdryer.
All help gratefully received

Thank you

Now it's trying to unlock itself. Honest!!

Take the back off and the battery out. Put everything into a bag/bowl of uncooked rice for 24 hours. The rice will help to absorb some of the water from the phone.

cool. Will give that a go