After completing level 55 (max level) at Prestige 10 in Black Ops II, you will unlock a new Prestige level called Prestige Master. Once you are Prestige Master, you will no longer be able to use Prestige Awards because you can only have one Prestige Token available for use at any given time. If you have a Prestige Token that is not spent when reaching the next Prestige level, an additional Prestige Token will not be awarded, and any unused Prestige Tokens are removed.
Although reaching Prestige Master unlocks all of the in-game options, the removed Prestige Tokens are not awarded. This means you cannot create a new Class Slot, you cannot request an Unlock Token Refund, and you cannot choose a Fresh Start to reset all of your stats and progress. In other words, Prestige Master means you have reached the highest level in Black Ops II, and you will not be able to start over again.
Example: If you did not use two of the Prestige Tokens while leveling up and the last two Custom Class slots are locked, those slots will remain locked when reaching Prestige Master.