Thanks for your query.Based on the facts that you have posted it appears that you have multiple Sebaceous Cysts over Scrotum
since many years.
Scrotal skin is re\ich in sebaceous Glands and hence more prone to get sebaceous cysts.
Normally no treatment is required but may need to get excised in Toto if increase in size or get infected and for cosmetic reasons.
Please consult some qualified surgeon for clinical assessment .He may decide about excision.