There can be a tissue rupture or any ligamentous injury. Consult a physiotherapist.
Next Steps
Go to a physiotherapist.. Ultrasonic therapy +wax therapy +some strengthening exercises will be helpful for sure.
Health Tips
At home.. Rest +hot water fomentation +pain killer gel +no long standing /walking +no stair climbing +use crepe bandage +wear shoes+no hanging of legs +frequent ankle movements +keep your foot elevated +no cold exposure.