If you use a rubberband on a keloid will it grow back?

Bad idea!!: Keloids have a high tendency to come back. When you remove something by 'tying it off', the subsequent wound does not have clean, sharp edges so you are already setting it up at a disadvantage to heal well. Keloids should be removed and treated by plastic surgeons to minimize the chances of recurrence.

Ligatures cause pain: Trying to kill off blood circulation to an appendage to remove it can be successful but does induce ischemia, necrosis and pain as well as a tissue response in the adjacent tissues that is not ideal for problems like a keloid. See your local plastic surgeon and s/he may be able to give you better advice considering they will be able to evaluate you in person.