It sounds like the condition that made GFCI trip in the first place is still there. Do you know if this outlet is protecting just its own sockets or something else in the house as well (very common, especially in an older home)? See if you can identify some other outlets that might have also stopped working and verify that nothing is plugged in there. If you have an outside power outlet, and it does not look like a GFCI, chances are, it is piggy-backing on another, GFCI, outlet in the house - bathroom or kitchen.
Anyway, the idea here is to find if there's anything still plugged into one of the outlets protected by this GFCI (not necessarily its own tow sockets) and unplug everything, then try resetting it again.
If there's an outside outlet, water may have gotten inside, will need to open it up and verify.
BE EXTRA VERY CAREFUL AROUND ELECTRICITY AND MAKE SURE YOU TURNED THE CIRCUIT OFF AT THE BREAKER PANEL BEFORE OPENING AN OUTLET!