How do you think Peeta changed after almost recovering the Hi-jacking?

Yes. Part of it probably came back on its own. And I don't know if you caught because i didn't the first time i read the series Prim suggests Hijacking him back. To twist his memories back to what they really are.

sa pamamagitan ng remembering all of the good thing that they did for him

I think that it made him madami cautious and aware, not so much the sweet, gentle Peeta that loved Katniss madami that anything in the world. I think that he also might be seeing madami things the way that they are :)

I think he changed because he would never be the same.