Turning time in PoA

[naetrobyn]

No: HPFGUIDX 97066

I'm completely new to this and to posting on any site, so bare with 
me if this question has already been asked (I can't find it in a 
search).
In PoA, Harry and Hermione go back in time.  the result is that Harry 
saves himself and the others from the dementors by producing his 
patronus stag.  However, I'm struggling very much with my idea that 
if Harry, in the 'first time' was attacked by dementors and given 
the 'kiss', that means he would have died and therefore not been 
alive to meet up with Dumbledore in the hospital wing to then go back 
in 'second time' to save himself.  I hope I'm making myself somewhat 
clear.  Please, if this has been discussed before, direct me to the 
information, and if not, please discuss!