Can it be a herx reaction?i started treatment for h. pylori, 2 abs and ppi, i also have mild infection(cough, little fever) syntoms worsen 1hr later.

No.: The jarisch herxheimer reaction is due to a massive release of foreign antigens into the blood. This would not happen with h pylori as the bug is not in your tissues per se and the load of organisms is not great.

Reaction: It should be checked out. You should seek medical attention.

Possible?: The jarisch herxhimer reaction is mainly known in spirochetes that are systemic, such as syphilis; the cause is supposed to be sudden widepsread exposure to endotoxin causing the reaction. H pylori is a spirochete, but is isolated in the stomach; it would be hard to have a systemic inflammatory response to such a localized infection, but if the burden was high enough, i guess it is possible?