>>527210106
don't delete anything
add edge loops that circle around the head and connect together in the back to keep the model symmetrical
the correct way to do it is:
1. start super low poly and let n-gons happen
2. cleanup and find all ngons
3. lastly add edgeloops around the back to keep the model essentially the same while removing all the ngons and increasing the polycount by a little bit

if you can't stand increasing the polycount, instead you can turn n-gons into triangle+quad.
when you do that, just pay attention and make sure you don't make strange-looking concave quads.


pic related was my crude attempt to explain the edge loops thing