Anyways, if you go to a 3rd country to get a stamp but didn't get it, you need to still have entries left on your current visa to come back in. If the visa on your passport is still the old one with the J1/F1 on it, or you used up the entries already, I don't think you'll be able to come back in without a stamp or new visa...
Sounds pretty risky to me...if I were you I would play it safe - after all you don't want to not be able to come back right? Visiting family can wait a little longer, or you can invite your family over here...either way, you need a waiver sooner or later, so why not start the process now? Better than trying to get it when you really need it, then it will be too late...
Good luck!