First, realize that traveling, physically, backwards in time is highly improbable, neigh impossible on the scale of a human being.
If you still want to attempt time travel, be prepared to accept that nothing you do in the past will 'stick' to the timeline you originated from.
Your interactions with divergent timelines are echos through the halls of time. On occasion, though it is very expensive in terms of resources, a time echo will settle down into the fabric of one or more timelines, giving the illusion of real change.
Alas, it is only appearances that seem to matter anymore.
So here I sit, broken hearted,
shit my pants, I am retarded.(Edited 14 seconds later.)