Only thing i can think of is too cut BIG eye holes and then use makeup on your eyes so they look black, the only down side is when your not wearing it you cant really put false eyes in, unless you paint some ping pong balls.
Theres possibly better methods though, and hopefully one that doesnt involve cutting ya mask.
All my mask for my self are foam filled. You need to make a ducktape dummy of your head mark where the eyes are. Then you take two pencils and push them throw the eyes of the mask in to the hole you marked in the ducktape dummy head. Then mix up two part cold foam and pour it in to the mask. Holding the mask neck and the dummy head in place roll the foam around till it stops expanding. Then after that is done let it sit and leave it alone for 15 min. When fully cured pull the dummy head out and your ready to go. The mask will fit like a glove and will not move if done right. Another great thing about a formed foam filled head is that it will never distort or loose shape, and you never need to stuff it or use a foam head to display it.
You also can use cushion foam and line the inside of the mask to make it fit better. I have never try it, but alot of people have and it works. Its a cheaper route and you can find all the materials you need at walmart.
My first mask I wore at SDCC was foam filled off DB's ducktape dummy head. It rolled backward and side ways. The weight of the dread pulled it all over the place. Never use someone else ducktape dummy is he has a bigger head then yours. LOL