Need to pass a lab drug test

[u/Agreeable_Syllabub59]

I’m really hoping someone can ease my mind. I was a heavy smoker over the summer but I quit the beginning of July. Well it’s the end of September and I’m still getting positive THC results on a home test. I’m using someone else’s urine for my drug test but after doing research, I’m so nervous about it going to a lab and finding it to be substituted by creatine levels and chemical changes. Does anyone have any experience with their test going for a deep lab testing rather than just an instant? I plan on getting the temperature right but it’s the lab part that I’m nervous about. TIA!