I am a wildland firefighter in California so I'm exposed to poison oak everyday when I train and even more often when I'm actually laying hose during the real deal. I found that bleach will end the blistering and swelling within a day (sometimes less time than that). The only thing about using bleach is it causes chemical burns to your skin so you really need to rinse the skin off about 5 minutes after the bleach dries up. From that point try to get your hands on some prednizone (steroids) to speed the healing process, and some calamine to keep the affected area dry without chemically burning it. That's really all we can do once we get it. Those three (bleach, calamine, prednizone) are easy to carry when working in the forest for days and weeks at a time and they do the trick. Good luck and be patient.