So this is the forth mask I've gotten in the mail, and by far the worst warp wise.
Step 1: Gather Materials
You'll need a hairdryer a horse mask (warped, duh) and socks.
Step 2: Get to Stuffing
Stuff the warped areas with socks.
Step 3: Melt That Sucker
Don't worry you won't actually melt it, your just softening the latex so it forms to the shape you gave it!