this has been going on for over a year now, ever since my old microsoft account got corrupted or something (i can't recall exactly what happened) and all of my things were restored, minecraft included, i was no longer able to see anyone's skins, i've tried everything i can think off, logging out and back in, reinstalling all of minecraft, every solution i can find just doesn't work, and after recently having tried to fix it, i can't even see my own skin anymore.

edit: so as it turns out the issue was some adware called premieropinion that had been installed on my computer without my permission, i had always been aware of its existance but i i didn't know if it was doing anything or not until i saw it on the list of malware that could be affecting minecraft, so i uninstalled it, and lo and behold i could see all skins again, so this issue has been resolved