Herxing is an overload of toxins, not just the presence of them. The toxins cause our symptoms, but if we have an overload of them so that the body is really struggling to keep up with the detoxing needs - that's when we herx. The more trouble your body has with detoxing, the quicker a person will herx and the more serious the herx will be.
My herx was severe enough to include 3 day migraines regularly, seizures for a week and an array of other lovely things. Got my attention!! I stopped treatment and started doing all I could to lower my toxin loads - I was suddenly a believer in the need for detoxing and detoxing well. It took almost 2 years to find a doc that would accept me as a patient after I stopped seeing the one LLMD that I saw in '07. I still did another 6 months of detoxing before my body was at a point to handle the influx of toxins that would be coming when I started the herbal treatments.
Clear as mud yet?