it is possibly a sprained ankle
try RICE that is rest, ice, compression and elevation.
minimize the use of the affected part.
apply ice but not more than 3 to 4 times a day only for 15 min each time.
compress the affected part crepe bandage. tie from distal to proximal. should not be to tight to compromise circulation.
elevate the affected part above heart level. try keeping ur leg on a pillow at night.
this helps gravity remove swelling