How to fill holes in a mask?

So I had to strip the paint off my TOTS H4 poster mask and reluctantly had to dremel the bits i couldn’t peel off. Unfortunately this time I had holes burned into the mask! I thought they would be filled by the latex/paint mix but I was wrong. I’m wondering if there is a way to patch these or fill them easily without making it look cruddy.

Mix a little talcum powder into some liquid latex. It’ll thicken into a paste that you can use to fill the holes