The FW dip will buy you some time, but not cure the issue. Some flukes are livebearers, but others lay eggs in the tank that can then reinfect your fish after every dip. One option would be to dose with Prazipro (be sure to have good aeration if you do that). Prazipro is mostly reef safe, it will kill feather dusters and sometimes there are bad reactions, but it is usually well tolerated. Another option would be to wait a week and try another FW dip. If the symptoms don't return, and nothing new drops off, you might not have to treat (unlikely though).
Jay