I have what was labled a sebbaceous cyst , by my doctor, he did not prescribe me any meds, I had ait for the last two years and it had a black speck in the middle It was causing so much pain that finally it came to a head and I was able to drain it flat, but continues to swell until I continuously press it to drain it daily, and blood , and pus come out with the fould odor. should I go back to the doctor. ?