Hi I Have An Abscess On My Leg On The

Hi I have an abscess on my leg on the back of my knee and ignored it for a little and finally went to the er to get it checked out, they started me on medicine and when I got home that same day it popped and released some puss, the next day it popped more but it was just a lot of blood and now the abscess and the area around it is purple and blue, I have a temp that is fluctuating and a bad headache do I have an infection and should I go to the er to get it checked