Suggest Treatment For A Bump With Greenish Discharge

On the back of my neck almost center just below my hair line I have what appears to be a boil it is opened with greenish discharge. I am taking antibiotics but the pain is radiating around my neck into my shoulders and upper part of my back. I went to a walk in she seriously just looked at it said here's some antibiotics I don't know if it's a spider/bug bite but it doesn't look good these may clear it up. That was 3 days ago. It's not feeling any better