Making custom skins again, loading into the game (using Forge, Overwolf), I have tried loading in using the normal Minecraft launcher (on latest release to test it j.i.c.) and same issue. My custom skin loads in for a brief second, and then turns completely white. I've tried uploading different skins, and same problem. I've used the skin editor in the past with no issues. I have also tried uploading the skin to minecraft.net, also has not worked.
I'm in a single player world, my graphics drivers are up to date... etc. I am running my modded world in 1.15.2.