I would suggest that you do your treatment again the day of the test. There isn't any proof that any treatment actually removes the THC metabolites from your hair.
It will help you pass a drug test by "tricking" the test into thinking you are clean or under the cut off limit.
As an example I will use the dilution method for a urine test. Dilution doesn't remove THC metabolites from your system. Only time and exercise can do that. The dilution method just "tricks" the test into thinking you are clean.
The same with hair. Once the THC metabolites are deposited in your hair they remain there until that part of the hair is cut off or you go bald, which ever comes first.
Good luck. I think you have good chance of passing the "real" test.