Did you get this problem sorted out? Are you aware that Hetrazan 100 is the drug of choice (diethylcarabamazine) for treating lymphatic filariasis. I find it very odd that a physician might give you this antihelminthic drug without telling you which worm/nematode he or she was trying to treat. The adult worm does reside in the lymph vessels of the scrotum and can cause very significant problems over time if left untreated.