The pin-prick test works but there is a vast difference in feel and look between "mushy" rot and dehydration. By the way, was that cutting in a sealed baggy or a baggy that could breath? I have never stored my cuttings in any sort of plastic but I wouldn't think it would be a good idea to store it for 4 months in a sealed plastic container. And we don't know how old the cutting was when you got it.