hello Thanks for query . Based on the facts that you have posted the lump that your husband has since a long time which burst and drained out large amount of stinky white fluid is most likely to be a Infected Sebaceous Cyst . The scrotal skin is rich in sebaceous glands and hence prone to get more sebaceous cyst due to accumulation of sebum beneath the skin. Normally they fade away without treatment however they need to be treated if increase in size or get infected. Give him antibiotics like Augmentin with anti inflammatory medication like Diclofenac twice daily .It should heal up within a week . If persists even after taking antibiotics you will ned to consult qualified General surgeon for evaluation and get it removed in Toto. Dr.Patil.