By far the most common podiatric occurrence in ballerinas is chronic neuralgia (pain) caused by nerve damage to the feet. There’s a condition called peripheral neuropathy that can cause generalized or pain numbness in a region, but I do know quite well (from person experience) that chronic pain in a region can lead to insensitivity in general, just by the brain blocking it out.
However, if your feet still don’t hurt even when you’re consciously aware of the damage to them, the only real reason I could think of is peripheral nerve damage. This is most commonly caused by diabetes, but is also found in a significant proportion of ballerinas who start on pointe before 14 years of age (mind you, this was only one study I found, but it was well-performed and a few hundred girls).
If you’ve broken your feet several times, you probably know a podiatrist or two in your area, and I’d ask them for more specifics on your case; I’m not a doctor, nor do I know everything about what’s going on with your feet.