Can an adverse reaction from ssri cause permanent brain damage, and can serentonine syndrome cause you damage? Hard to think, speak much still dazy

Yes but rarely. Most ssri reactions are short-lived and usually not serious. But the "serotonin syndrome" which comes from overloading nerve cells with serotonin can produce disastrous results including fever, muscular rigidity and death. This comes either from overdose or combination of drugs which interact with serotonin receptors.