回複：回複：回複：Help: 有關移民加拿大移民的問題

You can go back and apply a J1 visa. That has nothing to do with your waiver as long as you will not prolong your J1 program after DOS approval.
But if you are subject to background check, you will get visa after several weeks, or several months.
The best way I think is to apply a new visa in Mexico or Canada, you can still come back to US even you are requested for a background check. But if your visa is denied, you have to go back to China directly.