This is not medical advice and should not be taken as such. I am posting this for educational and informational purposes.
Those who are vaccine injured with experience very similar symptoms especially those injured by the covid vaccine. The approach to healing from vaccine injury would be much different then healing from severe infections.
Herxing is what most who are ill get when they have a pathogen. It is from the excitotoxins and endotoxins produced from the dying pathogen. It is why we should ease into killing pathogens off. Too much die off can overwhelm the body causing sepsis then herxing is only a minor part of the problem. This happened to me. Many herbs kill pathogens just as well as antibiotics. Even though many naturals do not have the side effects medications do you can still develop sepsis if you kill too much too soon. The Jarisch-Herxheimer reaction can be dangerous. It is why I believe a person should slowly ease into killing pathogens. Some of the damage from a Herx reaction can be permanent, it could even cause death. When I took wormwood the herxing was very bad so I backed of and took a very low dose then I slowly built up as my pathogen load started coming down. You will be able to tell because the herx reaction will not be as bad but when you increase each time you will herx again until eventually you can take a full dose with very little herx reaction.
http://www.lyme-symptoms.com/LymeDiseaseInfo/Die.Off.html
https://www.lymedisease.org/lymesci-herxing/
https://www.truthcures.org/tickbite-sepsis
https://rawlsmd.com/health-articles/lyme-herxheimer-reactions-your-guide-to-feeling-good-again
This describes the symptoms and suggest some ways to deal with it.
http://candidaspecialists.com/candida-die-off-symptoms/
http://blog.probacto.com/everything-you-need-to-know-about-herxheimer-candida-die-off/
https://www.jillcarnahan.com/2012/11/17/tips-for-dealing-with-herxheimer-or-die-off-reactions/
Best way to describe a herx reaction is all heck breaks lose. Almost killed me, I was bedridden for months. It is best to start on low dose antibiotics and work up. Also do the same with herbs that kill pathogens.
https://www.ncbi.nlm.nih.gov/pubmed/28077740
many think it only happens with Lyme infection but it can happen with any type of infection.
https://www.ncbi.nlm.nih.gov/pubmed/28115662
https://www.ncbi.nlm.nih.gov/pubmed/22607395
You can get a rash all over your body. This happened to me but not as severe as the man in this report experienced.
https://www.ncbi.nlm.nih.gov/pubmed/29687066
If the Jarisch-Herxheimer reaction is severe enough it can result in renal damage, cardiovascular damage, it can even cause damage to the eyes.
https://www.ncbi.nlm.nih.gov/pubmed/24022644
https://www.nature.com/articles/eye2008204
Even the blood is effected.
https://www.ncbi.nlm.nih.gov/pubmed/22567483
It can even result in a person having a stroke.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4238263/
It even results in a cytokine storm similar to that caused by vaccine injury.
https://www.ncbi.nlm.nih.gov/pubmed/23732875
Have a dental infection. You can experience a life threatening herx.
https://www.ncbi.nlm.nih.gov/pubmed/22707695
It can effect the brain.
https://www.tandfonline.com/doi/abs/10.3109/00207450903149217?journalCode=ines20
It can be life threatening.