How can I revive dried out fudge?
In order to save your fudge, you need to rehydrate it. 

One way to do so is to place the fudge in an airtight container with some source of moisture and leave it to absorb overnight. This could be: 


A bowl of water
A damp paper towel
A slice of non-stale bread


You could also gently heat the fudge with some moisture. This could be done:


In the microwave - microwave in short increments with a glass of (warm) water, which creates steam for the fudge to absorb, until the fudge no longer feels/looks dried out
In the oven - wrap the fudge in foil with a tiny bit of water, perhaps 2-3 teaspoons and bake at a low temperature (120-140C or 248-284F) for 10-20 minutes, or until the fudge no longer feels/looks dried out