Wait- you mean he told you to "stack" the ring for 3 months? As in remove it and insert a new one every 3 weeks? If so, then yes, you should be fine. But you may get some spotting from continuous use. Or you can also leave the ring in for 4 weeks, and out for one. (or in for 4 weeks, remove it and insert a new one without a withdrawal bleed.) I do it that way. Seems like you just get a little more for your money like that.