In what sense is Gregor's new physical form analogous to: his internal state? his role in society? his role in his family?
1. It is apparent from the surreal trapped state as a "monstrous vermin" that in reality Gregor has felt himself confined and repulsive, without value, reviled by others and alienated. As a traveling salesman, he has certainly been without friends or even associates. Gregor feels that "[H]e was a tool of the boss, without brains or backbone."
2. When he does not report to work one day, the representative comes to his house, even though he has not missed a day before. Clearly, there is no regard for Gregor's personal welfare or his feelings; he is merely a drone for the company. For them he is merely a worker, a cog on the wheel of the machine of commercial enterprise. His personal sacrifice for the company where he works does not lead to any reward, but only to the lowest of forms and confinement, and, at best "temporary and constantly changing human relationships which never come from the heart."
3. Most distorted is the change in the dynamics of the family that Gregor's new physical form represents in its surreal form. For, just as he has become incapacitated as his body has been trapped inside a huge hard shell, his family has become dysfunctional and inept: the father has lost his self-respect and place as the patriarch once he depends upon Gregor to sustain him; likewise, the mother and daughter are indolent and losing their beauty. For, once they rid themselves of this "dung beetle," the family's spirits revive and they again take charge of their own lives. When they leave and take a train,
...it was like a confirmation of their new dreams and good intentions when at the end of the ride their daughter got up first and stretched her young body.
Having freed herself from dependence upon Gregor, Grete's beauty is restored and she "blossoms" into a good-looking, shapely girl."
Truly, Gregor's distorted and repulsive form reflects the unnatural and reviled role that he has assumed with his family and in his society.