Would endocarditis show symptoms within the same day as your dental visit?

Not usually: Endocarditis (particularly after a dental visit where the bacterial inoculation is not huge) is usually a slowly developing condition that occurs over several days to weeks (or sometimes months). Unexplained weight loss, low grade persistent fever, decreased energy, little blood blisters under the nail-beds could all be signs. Blood tests including multiple cultures help make the diagnosis.

Endocarditis: The "full-blown" symptom of endocarditis take several days, however, you may develop fever as the bacteria enter the blood stream (bacteremia). It is probable that in most cases the bacteria is cleared by the immune system, however sometimes the bacteria can settle in certain areas such a damaged or a synthetic heart valve and form vegetations (it takes about 5 days to be detected by ultrasound).