It would appear as if the charade is over. You know that the Amulet of Draconic Subversion that Myranda the Hag created for you will not function inside Blackrock Spire. Perhaps you should find Rexxar and explain your predicament. Show him the Dull Drakefire Amulet. Hopefully he will know what to do next.
From the skulls of our enemies is shaped a medallion. You know this medallion, yesss? You have no doubt seen it worn by your elders.
Take it, whelp. Return to the Spire and present it to General Drakkisath. The General will place the final enchantment upon the medallion, attuning the trinket to your spirit.
You will wear the finished medallion as a badge of honor, symbolizing your ascension to one of our most guarded ranks: Guardian to the brood mother.