I think he meant that the boil is the indication that the OP process has started, is working. Toxins are being stirred up and sent out of you. May not be pretty but it's what you want.
Within a week of beginning OP, I had a huge, huge, hige zit -- perhaps it was of "boil-esque" stature -- that within a relatively short amount of time was gone, along with some others that had taken up residence. My first reactions to its appearance was, "Sh*t!" this is just making a bad situation worse!" and, "This kind of thing works for others, but never for me."
I am glad I persevered through those feelings and kept on pulling; things got markedly better very quickly! And those early feelings of its "not working" and of my being so damn special that what worked for you guys wouldn't even begin to touch me...well, I saw that those were not true, either.
I tried to keep those things in mind (trust the process, learn from the experience of others) when doing my first two liver flushes, too. And instead of giving up when the results were not what I wanted/expected, to feel confident that it is important to keep on going. (With a little help from my friends here at the OP forum!)