Fade to inside of rip

[altereddezignz]

Lets say you have an area that looks like it was ripped. How would i go about making a inside shadow to look like the inside was deep in illustrator. I can get the sahdow from the top by doing a drop shadow that is blurred but how would i make the shadow come up from the bottom. Thanks

I can post an image if that helps.

 

[rjssigns]

If I understand what you're asking here's my stab at it:
Make a rough shape on a sub layer then use drop shadow or inner glow. Manipulate until you see what you want.

There's another way too, but you would need to use PhotoShop and a Wacom Bamboo. Dead simple and very precise.

 

[altereddezignz]

This is not my file and only one i found online but this is kinda what i am wanting. How the inside is all faded from edge in to make it look deep away from the actual rip or tear hole.