What Causes Dent Filled With Foul Smelling Material In Face?

Hi, may I answer your health queries right now ? Please type your query here...2 years ago i got a cortisone shot for a small cyst on my face but the next day it formed a pea size dent.within a month it was filled with pus .now it is filled with thick fowl smelling material.i do not drain it because the dent starts to reappear.