usually thc stays in your system for about 45 days and since it was a few months when you last smoked it should be out of your system in no time but the best advice i can give you is to make sure you don't smoke between no and then and to be pounding water like there is no tomorrow you do that any it should be out of your system by then or you can try niacin which can be found at gnc but you have to make sure that you pound water because it will pretty much burn it out of your system if not you will be hot all over and itchy all over.