Hole in my mesh?

Im trying to make a mesh of a person, but when I switch to textured mode, there is a big hole at the side of his head, but there isn’t a hole in my mesh. Is it just my computer, or is something wrong with my mesh?
Im really confused.

Editing the mesh
The hole

“holes” in textured mode are usually caused by normals pointing the wrong way. press ‘Ctrl + n’ to recalculate the normals to point out from your mesh. If that doesn’t help enable the ‘draw normals’ button in the ‘mesh tools and more’ panel to see if there still is some problem with the normals

You may also actually have a hole in your mesh. Here’s how to fix that.
In edit mode with snapping on, select on of the vertices in the side of the hole.
Hit ‘E’ for extrude and go across to another vertex on the other side of the hole.
The object is to get four points so you can fill the mesh face.
As you stretch the line to the other hole, hold Ctrl and it will snap to the vertex when you get there.
Go into Edge select mode (as opposed to vertex select) and hit ‘W’ to subdivide that edge if you have to.
After you do that and have all you open places surrounded by 4 vertices, select all 4 and hit ‘F’ for Make Edge/Face.
That will fill in your hole.

Sorry Morio, im such a n00b.
I don’t know what the “mesh tools and more” panel is.

In edit mode, press F9 to get to the Editing tab (the one with the icon that is a square with yellow vertices). At the right of this box is Mesh Tools More.