You can also try something often referred to as "Cabopatch" . I've never tried it on silicone, so I'm not sure that it would work, but it is used on foam appliances and skin to hid flaws and seams. It is cabosil mixed into prosaide. It creates a paste, and can be spread over areas such as the seam between the headpiece and your forehead and smoothed out to help hid it. The cabosil thickens it enough to create a texture, though not a heavy one, so it doesn't stand out as a smooth surface. I'm just unsure if it will stick to the silicone, and leaning towards that it won't. I can send you a little bit if you want to try it out though.