I thought I'd add my 2p worth.
I too lost Touch ID after updating to 8.3 the other day, so earlier today I looked in Settings>Touch ID & Passcode and "Use Touch ID for iTunes & App Store"was set to off.
I set it back to on, entered my Apple ID password and all everything was back to working again.
I too lost Touch ID after updating to 8.3 the other day, so earlier today I looked in Settings>Touch ID & Passcode and "Use Touch ID for iTunes & App Store"was set to off.
I set it back to on, entered my Apple ID password and all everything was back to working again.