I would first read through our [http://www.ifixit.com/Wiki/Electronics_Water_Damage|electronics water damage wiki]. This will help prevent further damage to your phone. Use our [http://www.ifixit.com/Device/iPhone_4_Verizon#deviceGuides|guides] to help you take the phone apart for cleaning and inspection. If the screen still looks odd after you've cleaned everything you may unfortunately have a damaged screen and will need to replace it. We carry the display assembly [http://www.ifixit.com/Device/iPhone_4_Verizon#deviceGuides|here], but hopefully cleaning things up the rest of the way will fix your issue! Good luck.