Recently 2 to 3 members reported me some of costumes not work properly . some have actually bugs i need to fix them (small bugs). but those people got some wired bugs. such as only showing the character hair . so if you got that issue . do this
delete all mods including signature bypass. and verify game file and again install the costume again .
if still not work try to delete full game and install it to new location (we are creating ~mods folder but some time its merge with the game original file and damaging the mods and the game )
if still its Not work download the game form Epic Game Lauchner . because I'm also using that version of the game and I'm testing costumes in that game (You can Bind your Steam game account using game settings)
if still not DM me and tell me what's wrong with the skin