My iphone6 accidentally fell into the clean toilet commode and fell with most of the phone in water with home button area fully inside. This happened at about 2pm and I immediately used dry tissues to clean it up. At first everything seemed ok. I tried to unlock my phone and Touch ID wouldn’t work.
So I kept cleaning my phone as there was water drops coming from sockets. By then I read up internet about immersing the phone in uncooked rice. So came home and at about 6:00 pm I kept my phone in rice. I let my phone battery drain by itself. It’s at 2% now.
Took the hair dryer and started showing near the charging socket area beneath the home button. By now I already removed the phone from rice. The phone heated up. So stopped the dryer and let the phone cool down. Meanwhile, I removed the already added finger prints and tried to add new. First success was that for about a second the phone tried reading my thumb impression and then stopped working. I tried many times and it won’t work. By now phone was about to die so I put the phone on charge to see if all well with battery. Thankfully it was. So I let the phone charge fully.
Used the dryer again few times and allowed the phone to cool down. Them tried setting up Touch ID and tadaaaa it started recognising by thumb prints.
I added finger prints and the phone started working normally. With a great sense of achievement I slept and woke up next morning to check if it’s working still and it worked!!!
So, try the hair dryer technique to revive the Touch ID. Good luck!!!