when you only smoke once thc leaves your body in a few days. when i was younger i smoked once or twice a week and i once got drug tested a few times 2 days after i smoked nothing showed up. i weighed about 120 though. thc leaves your body fast. UNLESS you have a heavy habit smoking everyday, then it takes about a month or two. so i think you are fine. drink tea if you are worried,
ummm
and thanks for representin the US
peace