Welcome and thanks for posting your query to HCM.
It appears from your problem that you are suffering from infected sebaceous cyst
Sebaceous cyst are formed due to collection of cheezy material in oil glands resulting in cyst like structures. These cysts re not at all dangerous in itself and remains for multiple years. The only problem with theses cyst is of getting infected.
Once these are infected these are to be drained and excised immediately.
In your case it got infected and now still pus is coming out. It need special attention immediately. So meet your treating doctor or best would be a surgeon to take care of the cyst and excise it completely.
Hope these informations are helpful.
"Wish you good health"
Dr Sanjay Kumar Kanodia
MD (Dermatology & STDs)