Theoretically speaking, if someone's foreskin grew back after his Bris Milah, would he need another Bris Milah? Is the idea that the Bris be permanent, and if the foreskin were to grow back, it would have to be cut again? Or is the idea that it be cut for the sake of the Bris Milah, so if it were cut once for that intention, that would be enough?
If it's the latter, what if someone drew out his foreskin? If the idea is that it's cut for the sake of the Bris Milah, his was, and perhaps even though he drew it out, he doesn't need to have it cut again. Or perhaps since he drew it out, he's intentionally undoing his original Bris, and so he needs a new one (as opposed to a case where it naturally grew out, in which case he's not intentionally removing it)?