My existing head have been splitting. The heads form a second mouth in the fleshy circle and then the flesh begins to pinch in between the two heads until they are two separate heads. That's been the way they've all reproduced. I don't know if it will recover the two existing heads. I'd probably be inclined to cut them off, especially if they looked like crap!
In the photo in my gallery you can see the right most pair of heads. Those two were one that had recently split. The top one is forming a second mouth and you can see the pinch point starting. The leftmost one is the one most recently splitting and I don't think it had a second mouth when I took that picture.