Unless an indictment comes down before Election Day, I think it's probably too late for this to have any material impact. Most likely Clinton voters aren't actually Clinton voters - they are anti-Trump voters. An indictment prior to the election would change things, but that will not happen. Clinton has almost no chance of losing.

Once she wins, she will then either short circuit the investigation by forcing Comey and anyone else associated with it to resign, or she will actually be indicted and then she will pardon herself. For the record I believe that both of the candidates are despicable human beings and either one will make the worst President I have ever had in my lifetime, but we are almost certainly stuck with Clinton for at least the next four years.