Thanks for your query.Based on the facts that you have posted it appears that you have developed Sebaceous cyst
The scrotal skin is rich in sebaceous glands hence more prone to develop sebaceous cyst due to accumulation of sebum beneath the skin.
Normally it subsides without any treatment .However if increases in size or get infected, you need to get it excised in Toto under local anaesthesia by a general Surgeon
. Please consult qualified general surgeon or Urologist
for clinical assessment and further treatment.