I smoked on or about dec 29 and had to do a surprise hair test in jan 18. I am not a daily user rather monthly user (maybe 2times a month ). Is there a chance the test would be negative? (20 bag )

It will most likely be positive, unless you did some sort of hair treatment (like bleaching or a perm). Otherwise it takes 3 to 6 months

It will likely be positive. Perhaps this is an indication that you need to return to treatment and work on things a little more. Don't think of the test as getting you in trouble, but rather as potentially saving your life. There's a better life for you than worrying about something like this. God bless and good luck to you.