There might be a chance that your fudge mixture might not have the consistency and texture you want it to have, and if it just doesn’t seem to set even after refrigeration, here’s something you can try.  First, try to reheat the fudge mixture- the most common culprit that doesn’t let your fudge set is the fact that the mixture isn’t cooked enough.  Just dump the fudge mixture back into a pan on low heat, and add a bit of powdered sugar into it, and continue to let it cook for a few additional minutes. The powdered sugar can help the fudge set if the mixture seems resistant.  If you’re worried the additional sugar might make the fudge overly sweet, you can use some evaporated milk instead.