KEY FOB NOT WORKING

Getting wet should not affect the RFID chip (which starts the car even with no battery installed in the key fob) which, by design, is a sealed unit.

I would look at other things before going down the path of replacing the key fob.

Have you actually done an analysis of the 12 V battery to make sure it is fully charged and in good condition?

 

I speculate water entered the circuit board compartment (bad battery seal AND/OR rubberish buttons have cracks not visible to your eye), thus the inability for SKS to function properly. The intrusion of water is shorting out the communication of the SKS FOB to the car.

READ POST #5 and the related links w/in it, to understand why buying used SKS Fobs will be a waste of money and time, esp since you want to retain this function.

Verify with a Toyota dealer that this is the part number of the SKS Fob (89994-47061).
A 100% NEW, virgin, SKS Fob might be available on Amazon.
Camelback Toyota is another good online option; 2007 Toyota Prius Parts - Camelback Toyota Parts - Genuine OEM Parts - Free Shipping

Become self sufficient. Search "genuine Toyota parts"
You will see many links to sites that sell "genuine Toyota parts."
You just need to exert some effort and peruse the sites to see which one has what you want. Some sites are genuine Toyota dealers who sell genuine OEM parts online. Some sites are sites that might sell OEM parts along with non-OEM parts. Some sites are just large non-OEM parts sellers.

 

when they jump the car?

 

Would have been very useful to include in Post #1.

B/C Post #2 would have likely asked about the jump being done correctly or incorrectly, and inquiry to check on the fuses.