One morning I saw a very tiny white pus like pimple on my left left leg, just above my ankle and I accidentally punctured it. I thought it could be some insect bite. But after one day it was pink and tender to touch. After 2 days the area near my ankle was swelling and hard and is even a bit painful while walking . Please advise on what could be the possible cause and medication/treatment that I should undertake . Thanks in Advance. Attached below are some pics of the same.