Is there a way to get marijuana out your hair?
If you have chunks of marijuana in your hair, pick it out or comb it out. If you have the smell of marijuana in your hair, use shampoo. If your hair will be used to scientifically test for marijuana useage, and you have used marijuana, cut off your hair. Most likely if you're bald they'll ask for hair from another part of the body. If you're completely bald they might not give you a job. The only thing that can save you is to shave your head and get a wig that looks real and is made from human hair. But that would take a lot of work.
No, exposure to the smoke of marijuana does not stay in the hair forever, but duration does depend on the frequency and severity of exposure and frequency of washing hair. What does happen though is, if a person smokes marijuana there are traces of it that reaches the follicles and grows into the hair. A hair sample can be taken from the person and tested and can prove that he/she smoked marijuana.