I found the key to Skinamarink - CPTSD

Throughout the film, the parents didn't do anything to hurt Kevin and Kaylee - it was the Strange Voice. I believe that the Strange Voice is the embodiment of the urges and insecurities that those with CPTSD suffer from - from childhood throughout adulthood.

When Kaylee did what the Strange Voice told her not to do, the Strange Voice took away her mouth (her ability to communicate with others) and her eyes (which obstructs your ability to understand events going on around you, especially as a child).

When Kevin is at his lowest point in the film, the only one he cries out to is "mommy".

Once Kevin has had enough after 500 or so days, he asks Kaylee (who, at this point, has been out of the picture of Kevin's life, so it wouldn't make sense for him to be talking to someone who isn't in his life anymore) if they could "watch something happy." At that point, we see the doors return to the house.

However, Kevin still suffers from the memory-affecting aspects of CPTSD - he flips through family album and can't make out anyone in the pictures. So much so, that the people in the pictures might as well have no faces or no heads at all.

The end of the film shows the mother disappearing from Kevin's life, but he is still haunted by the Strange Voice, whose face is the last thing we see. The face is not that of Kevin's mother, or his father, but an ambiguous outline. Thus, even when his parents are no longer in his life, he is still tormented by CPTSD.

Thank you Kyle. Wonderful film, and may be the first step in repairing my relationship with my parents.