Severe reaction to ankle strengthening exercises

Having suffered from some ligament/tendon damage to my left ankle, I tried preventative ankle strengthening exercises to my (so called) good ankle.
Theses included standing on one leg with eyes closed. I could only do this for about 20 seconds at a time. I repeated the exercises for 5 x 1 minute with a minutes rest in between.
Gradually over the next 5 days, I have suffered severe ankle pain, swelling and a lack of mobility that makes walking very difficult.
Did I over do it? Is this a normal reaction? What should I do from here? Any advice appreciated.