If i haven't smoked in about 2-3 months and i have to get a hair test done is there by any chance that weed could still be in my system?

In your hair: Hair testing can detect drug use up to 90 days or longer. So if you used 2 months ago, you might test positive.

3 months: 3 months should be safe, but I would recommend a hair cut

Yes: If you have been using marijuana for a long time before you stopped 2 months ago:It will stay in your hair for 6 months or longer after you stopped smoking it.