The ice weapons disappeared

[Joshua Pigram]

When me and my friend completed the scorpion waves we were both down and it finished but they didn't appear in my inventory when I went back they weren't there and also when we recovered our backpacks they still weren't there and unfortunately I didn't save the game so I couldn't re do it. 

Any tips or are they completely lost?

[Rabenschwarz]

Hi, You usually have backups that you can select when you start the game. You'll find multiple save games there. You can then select the appropriate one

[Matt__AsA__Hatter]

It's a recipe you unlocked.  You need to craft them.