Can you die by touching a fire belly frog then licking your finger?

No. It would taste absolutely foul, and you might feel quite sick, but a healthy adult or teenager would not die. Children are at increased risk, but it is likely you would be fine. However, it is very dangerous to touch any unknown frog or toad, and never lick your finger after touching any frog or toad, known or not. There is a risk of toxins or parasites.