Hello - It could be a variety of things - die-off - allergic reaction OR too many purifying herbs. You might have larvae that have settled into the left side of your sinus cavities - the HUMAWORM is killing them - thus the headache and swelling. I don't know of any under eye swelling caused by any of the HUMAWORM herbs, but I do know that swelling sometimes occurs where eggs, larvae and parasites are at the time of the cleanse. Some folks will have stomach swelling one day - then pass many parasites the next day - then the swelling is gone.
I am more inclined to say it's die-off, because if it were an allergic reaction, BOTH sides of your head would react the same way.
I don't know how many milligrams of purifying herbs are in your tea, but it might be too many of them combining with the purifying herbs in HUMAWORM. The chamomile, however, is fine. Be sure to drink plenty of fluids while taking HUMAWORM.
If the headache is more than you can handle at this time, stop the cleanse.