Board Thread:Skyrim/@comment-12736981-20130719205247/@comment-72.71.207.204-20130720103623

One thing you could try, although I haven't tested it, is to use the console command psb (player spell book), which supposedly unlocks every spell and shout in the game including ones used for testing. If the spell doesn't appear after that then it is likely that you will need to seek a mod. This wiki does warn that this console command may cause bugs.