How to get my skins back?

[Frishy]

I no longer spawn in with my normal skins, like the birthday suit and witch hat for example, but I have the achievements in steam for them. I haven't deleted any files or reinstalled, I haven't switched computers or anything.
So how do i get them back? Can I even complete the achievements I already have unlocked? :(

[Chaser the Tiny Hippo]

What I did when this happened to me was uncheck "give survivor starting items"(or whatever it's called) then I suicide and respawn. After that, recheck the starting items option, suicide again and you should have your stuff back.
This only worked for skins you got that were related to achievements. Any skin that's not tied to an achievement is gone now, and you'll probably just have to do the action to get them again.