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Based on the description given it could either be a Sebaceous cyst or a furuncle.
A furuncle is extremely painful and may cause fever
. Small furuncles
can be treated with antibiotics and if large drainage
should be done.
As you have mentioned it neither increased nor decreased in size , the likely possibility in your case is Sebaceous cyst. Pus coming out from the swelling could be due to suppuration of cyst. Small asymptomatic cyst
can be left alone. Removal is required in case if it is infected or increasing in size. Surgical removal is an elective procedure . Hence can be done whenever you wish to have.
Removal of the cyst is the definitive treatment. Do not worry, it is a very small procedure. It hardly takes 15 mins to finish ( requires no general aneaesthesia and can be done under local)and you dont need to stay at the hospital.
Please see a doctor and take his advice regarding treatment.
Wish you a speedy recovery and all the best for your exams