My initial advice? Put the whole thing in your airing cupboard for a couple of days - long shot is that it may still be damp!

I found a workshop manual on the web for my FZ20 with complete dis-assembly instructions. (Not for the faint hearted) There may be one for the FZ50.

Then haunt eBay until you can find a parts FZ50 - perhaps one that has a smashed lens as a result of being dropped. The EV viewfinder should be intact. Remember water damage is normally fatal if the battery is in place (that includes the internal back up one)

Consumer Warning
Please treat any dismantling/maintenance advice by me as extremely suspect!

Why? I have severe dismantleitis (incurable unfortunately) and have more dismantled cameras in boxes awaiting resurrection than hot dinners!

Paul