My tendon rupture was caused by chronic damage, not a sudden incident. I have such severe overpronation (or such flat feet!) that my tendon had been tearing over the years. The tendon had been stretched and fibres were tearing off, little by little. I had no idea of this although I could see that my feet were very flat, the arch is virtually non-existent.
I knew exactly the moment that the tendon finally ruptured as I was getting out of bed in the morning, stretched, (as you do) and felt a sharp, stinging pain when the tendon finally went. I didn't realise what I'd done (put it down to old age) so carried on as normal for three months. The area where the tendon had snapped was swollen and inflamed - felt very hot to the touch. It was also just a tad painful! Eventually I went to my GP where I was given a series of misdiagnoses until I finally saw someone who got it right. I was referred to a specialist, my foot was strapped up and I was on crutches until I had surgery. I was in plaster for a few months afterwards and then began recuperative work 6 months after the surgery.
All in all, I was on crutches and in plaster for around 12 months, but that was largely due to the fact that it took four months after I'd ruptured the tendon before I had surgery. I also developed osteopaenia because I'd been non-weight bearing for so long, so where the tendon passed through the bone, the bone started to crumble, damaging the tendon, so I had to go back into plaster to sort that out.
I also had surgery to reposition my heel bone as the tendon problem was partly due to skeletal problems, so there would have been no point in repairing the tendon only for the same bio-mechanical issues to cause further problems years later, so there was not just the tendon but also broken bones that had to heal.
I do the exercises described by runnersbeen above and also foot flexibility pretty much every day. I do get twinges from both tendons, but as long as I look after them and am sensible, so far, it's been OK.
I wear full length orthotics and (in spite of what others say) still have to wear stability / motion control trainers.
If your pain went away relatively quickly, then it sounds as if you may have caught it in time. If you get professional advice, see if you need a podiatrist - they're generally better at foot support etc than a physio who can usually only provide OTC supports. That may be sufficient for you, in which case, great, but if not, then a pod can be worth their weight in gold!
Good luck, hope it's not too bad.
