How can I remove sharp edges from the final render? I'm un-wrapping my mesh and these are all my mark seams:





When I render these are the results:



It seems pretty god, but when I went in the back, near the neck I saw them, straches all long my mark seams.



Did I make something wrong or is it usual with mark seams? What can I do in order to smooth this one and render my figure better?
Delete the vertex of the defective area.  Examine for unwanted pixels.  Add back a new pixel.  Correct Seams if required.

Examine the troublesome area in question in Mesh Select Mode vertex, edge, and face view while in Edit mode and remove, adjust stray vertices.