You can, subject to whether the water ingress has reached the bottom screen.
You should also be aware the touch screen can be adversely affected by the disturbance. If it is damaged it will require replacing also, and the touch screen is more susceptible to water and physical damage.
The exchange, carried out by a local repairer should cost about £20 - £30, subject to whether the touch screen is affected.
new_home, February 2010