HI Emma, most will NOT allow a plastic bar, the reason you need remove piercings is they heat up during surgery, this means metal will burn you and plastic can melt, the only piercing that would be safe to use is implant grade titanium which is usually for dermals only. After 5months the Fistula, or channel for your piercing sits in should have started to form so if you take it out mins before you down and put it back in right after it shouldn’t close. Hope that helps x