For how long after anaphylactic shock we expect after effects & what after effects?

1-2 days: Developing anaphylactic reactions involves many organs, depending how severe the reaction was. If it was treated as out patient and did not need intubation, usually a few hours to a day the person feels tired. If the person was ill enough to be intubated and admitted to the hospital, the time to resuscitation is key for brain preservation. So it is variable.