So after watching a particular video by Mike Mew about orthdontic retainers and mewing( https://www.youtube.com/watch?v=dPlse4UoMLQ)

I realized that over the past year of me mewing I have actually caused detriment to myself by mewing and then wearing overnight retainers. I don't find it to be all bad as I have perfected the technique of mewing but I have conducted an experiment over the past 3 months and I would like any opinions on the validity of it.

In the video Mike Mew mentions the most friendly of the retainers to be a fixed retainer which only covers the first 4 teeth as it allows for palatal expansion and proper mewing. I have 2 pairs of essix retainers. I dropped my retainers for a month to discover a lot of relapse of my front 4 teeth on both top and bottom, so I decided to take my extra pair of retainers and trim them to fit only the top 4 teeth. It has been 2 months since doing so and I have not experienced any relapse in terms of my teeth becoming crooked but rather I have experienced some palatale expansion and my old retainers seem to be slightly too narrow for my mouth now. Is this a valid option or should I go to my orthodontist and pay to get a fixed retainer.