Thanks for posting your query.
You might get ankle bruising as a result from cumulative stress
on the bones of the foot or ankle after prolonged walking . Certain risk factors can increase your risk of bleeding and therefore susceptibility to bruising as well, such as blood thinner medications, low platelets or blood clotting disorders.
I advise you to apply ice packs over bruise
area, take anti-inflammatory drug under guidence of your doctor. avoid putting full weight and rest well for few days.
Wishing you good health
Dr Saurabh Gupta