Hello Andrua and thanks for the query
You should be worried as you have pus discharging from the last 7 years. It should be cured as soon as possible. In my opinion you should go for pus culture and go for the proper antibiotic course and if the pus culture is sterile than you should go for removal of the lump as per your doctor's advise. The biopsy
of the material helps you to get to a diagnosis and finally get treated as per the diagnosis.
So do not delay your treatment and follow your doctor's advises.