Rogue Poison Quest Bug

So i just completed Hinott’s Assistance, and recieved Hinott's Oil, i didnt have to drink it because the poison was already dispelled, i completed the quest (as in completed quest) but he didnt teach me "poisons" skill, any known fixes or something i could do about it??

In WotLK doing the quest doesn't give you the skill. The quest remains optional to complete from previous xpac.

Patch notes: Patch 3.0.2 (2008-10-14): Poisons skill removed. All finished poisons are available on vendors rather than created by the rogue.