HI Thank for asking to HCM I really appreciate your concern, this is very common complication being noted in vasectomy, due to the loose skin the infection parts spreads up very quickly and became painful, if I would be your doctor then I would treat you with Ibuprofen with Acetaminophen three times in day, I usually prefer Boric acid powder for fermentation, this is to be mixed in hot water (Boiled then bring the temperature at suitable level ) the boric acid about 5 gram should me mix with one and half litre of water then pour the water on swelling part, this also give quick relief, have nice day.