Will I p the hair follicle drug test? What do I do to p?

Ok, yesterday i was at a party. I was a little bit inebriated and made some bad judgements. I had about 4 inhales of some "hydro" marijuana. I realized after I smoked that that I have a hair follicle drug test in about 3 1/2 months for a job opportunity with GM. Ive never smoked marijuana before last night, and I am not going to smoke it again. Will I p? What should I do to increase my chances on ping? I was thinking about growing my hair fast with rogaine or something.