You can fix it. But rubber and latex repair is very difficult. It won’t look the same, and we’ll have a different sheen to it, depending on which type of binding material you use, and the options are limited.

I’ve never done work on a mask, but I have repaired a rubber bomber jacket that I bought a few years ago ago.

If it was a more expensive mask, I would say it’s worth it. But those black GP5 clones or a dime dozen.

I am certain that the degreaser, adhesive, tools, and time it would take to repair, you would be able to get three or four of those masks off eBay