I'd normally vote with RootCause on this one, but I would think it won't work with sil, since the moisture will never actually touch the fabric.
You might try a hair dryer first, as that will let you heat up the material and smooth it out with maybe a book or something heavy, without risking melting the silicone or fabric.
If - if he stood! Enough of ifs!
He knew a path that wanted walking
He knew a spring that wanted drinking
A thought that wanted further thinking.
A love that wanted re-renewing
"A Lone Striker" Robert Frost