Go buy GE1 clear silicone caulking (and a caulking gun if you dont have one.) or Dap- all purpose silicone adhesive from Home Depot or another hardware store. Then get some pantyhose in a color similar to the mask. Turn the mask inside out. Pin the ripped area close and use the glue to glue the pantyhose over the rip. Once its dry, turn it rightside out and fill any noticible gap with the glue. Wait overnight and its wearable! - we've found that the thicker you use the DAP, the better it works, when you thin it out it doesn't set well. GE1 Clear silicone caulking works really well and is our repair material of choice.
The glue is much less flexible than the mask silicone so use sparingly.
Learn the proper way to put on your mask and take it off. Its very important!
Contact us and we can fix it for you so that's its just about good as new. Of course, if its not brand new, it may cost ya.
If you decide you want to fix it yourself and you have the time, you should order some power mesh and sil-poxy adhesive from our friends at Reynolds Advanced Materials. You'll also probably need some silicone, tints and thickener. Talk to them. They're awesome and tell you everything you need.
Don't have the time to wait or the money to spend?