Wall thickness mask

Hu Guys,

A friend of mine is creating Furr Masks. She did send me an STL and when I printed the file the walls are flimsy thin. Can’t get the walls of the mask thicker. Can anybody help me creating this mask with wals of 1.5 mm or 2 mm?

Can’t upload an std file here. Any ideas to share the file?

Thanks for the help!

Al