You should remove the poles of 6 edges that I marked in the image with red dots. Also triangles (edges marked in yellow). A possible solution to the E6 front is cut with K by green lines.
There must always be at least one row of faces from 2 loops to avoid poles 6 edges. In the other image in all cases it is part of two loops that do not fulfill this condition and therefore there is a polo E6. There are various techniques to remove it, for example:
In case 1 I created a row of faces that separates the two loops. This increases the number of faces in the mesh.
In the second case I’ve merged the vertices marked with ALT + M. There is a face less in the mesh.
In the third case I’ve ripped with the selected vertex V and created a face in the resulting gap. There is one more face in the mesh.
In all cases the original loop flow is maintained.
Case 4 could be the mouth: red loop is not closed and extends through the mesh. Uniting the 3 rows selected in one edge, we close the loop and eliminate the red E6. (Pictured is a E5 because I have not set below red mesh loop).
In this case the flow of red loop is changed, but it is better because the deformation is contained, and the result is a mesh with less expensive than reacts better smoothing.