In some ways better still, I got her to actually engage with me as an intelligent human being. My understanding of the nature of the problem is now as follows: The achilles tendon (of which mine is fine) moves within an outer sheath; the sheath became irritated by unaccustomed or excessive usage, possibly exacerbated by shoes placing pressure on the back of my ankle. Six weeks of not flexing the joint has allowed most of the irritation to heal; there is some remaining irritation or scarring, which can be addressed by ultrasound treatments. I am free to walk in normal shoes, but should build up gradually; initially I am to continue wearing the not-a-cast if I am going outdoors (where uneven surfaces are more of an issue) farther than to or from a car. If gradually walking around more indoors does not lead to any new symptoms, I can start walking up to a half-mile at a time outdoors in a week, and work up from there.
So: perhaps dancing lessons in the spring.