If i smoke marijuana a few times a week how long would it stay in my system?

I have to take a drug test in about a month from now, would smoking weed a few times a week show up on the drug test? I realize the only way to make sure would be to stop, but is that necessary? I started because i was getting terrible migraine headaches that i would get extremely nauseous from and heard that smoking marijuana occasionally would get rid of my headaches, which turned out to be completely true. I haven’t had a head ache in months, and if i stopped for a month would my terrible head aches come back?