Make and bake cake according to box directions. As soon as it comes out of the oven, poke holes with the handle of a wooden spoon all over the cake. Pour sweetened condensed milk over the top. Let cool completely.
Next spread fudge over the cake, and put in the fridge to set.
When it is cool, spread coolwhip over the top and then top with crushed score bars. Refrigerate leftovers.