I was shopping on Amazon the other day for spray-on repositionable adhesive and I found a Krylon brand spray that had a lot of reviews where people were saying they used it to revitalize silhouette and cricut mats. I haven't personally done this (I don't own either device) but that MAY be an idea for fixing yours?
Here's a link to the product & the reviews:
http://smile.amazon.com/gp/product/B...=ATVPDKIKX0DER