Can't get the edge straight

Hi! I’m new to blender and I’m trying to build a head of my son but i’m stuck because I got a problem with edges that are curved and I can’t get the straight. Is it because I smooth them somewhere or else?



I tried loop cut,extract knife delete face and rebuild face… it come back all the time. The edge are bended instead of been straight. Any Idea how I can get correct that?
Thank You!

It looks like there are vertices there. Switch into vertex view rather than edge view, and have a look. It looks to me like all the faces on this mesh are N-gons, with more than four vertices.

Don’t enable subdivision surface on the editing cage, that’s why it shows up like that.
http://www.blender.org/manual/_images/SubsurfEditCageOn.jpg
Especially don’t model it on because it doesn’t show the real vertex positions. It’s good for minor adjustments.

i also thought that at first, but it looks like all the edges are bended. witch i would guess is cause he has subsurface modifier on.