Think about not catastrophising the possible outcome. If you do stutter what’s the worse that can happen? It’ll feel horrible but go beyond that. Stay with the thought and play out the whole scenario. Whichever way you cut it and even if you run with the worst case scenario nothing catastrophic is going to happen. Do this every time you have a fear of stuttering. Play the scenario through to the end and think about the outcome. It’s not that bad. Your brain will learn that the consequences of the action are nothing to be so scared/anxious of. It takes time but you eventually are just less scared of it.