Oh wow, something really did chew up that dome. I'm not too familiar with the Pro-X heads, but I'm pretty sure the dome is interchangeable. Can you push the dome out of the head? If so, is there anything scribed on the dome that would suggest what size it is? Once you know what you have you should be able to order a new one from CT. Worst-case, you could send the dome back to CT and have them identify it, and then send you a new one.