A writer's fears

It's amazing — even after three years of working day and night on my manuscript, I am still discovering various flaws in the story line.  While I have no problems fixing the ones I find, the fact that I seem to stumble upon them more or less accidentally makes me wonder how many will continue to escape my attention.   It makes me worry that quite a few will surface only AFTER the novel has been printed and distributed (even a single one would kill me).  What a nightmarish thought.