How long will it's take poison ivy rash to go away It has like these small red tiny bumps on both of the legs. And has this blister like line on it too. Is it poison ivy Or not?

If you want a diagnosis, see a physician. We can't tell you what your rash is based on what you think it looks like, especially if your description includes phrases like "blister like line."

A poison ivy rash can last anywhere from one to four weeks, depending on severity and what you're doing to treat it.