Hi Starkiller,

Welcome to the forums!

I could be wrong, but it looks to me if you've softened the edges in that particular part of the model, not sure how you could've done that by accident.
Try reselecting the edges that are appearing smoothed, hold down shift and the right mouse button, select the menu soften/harden edges, then select harden edges.
Or under the Polygons menu set, go to Normals, then near the bottom is Harden edge.
That may do it, if not hopefully someone else will have the answer.