mouse's sliding pads showing unusually high wear

[nightmarevoid]

About one-and-a-half years ago I bought a func MS-3 mouse as an upgrade from a friend's old death adder. I really like the func MS-3, but the sliding pads on the bottom of the mouse have been showing some unusual wear. On two of the pads, it appears that some thin plastic film covering it has come loose and essentially "bubbled" creating an uneven surface. On the other pads, the surface just looks like it's been lightly sanded, which is normal from what I've experienced. The bubbled parts of the pads sometimes cause the mouse to be hard to move.

 

I was wondering if it could maybe be possible for me to sand down the two bubbled pads using fine grit sand paper. What do you think would be the best solution?

[Flight1sim]

did it come with extra pads? I know a lot of companies do that