Is It Common That a Fascia Graft for Nose Will Dissolve In Time?

I happen to use temporal fascia grafting on a regular basis as part of my rhinoplasty and revision rhinoplasty practice here in San Diego, CA. It is quite normal for upwards of 9-12 months after surgery to see moderate swelling just from the fascia grafting. It can in many cases act like a biological sponge absorbing fluid before it truly settles down and shrink wraps around the nose. This can often times lead to that spongy feel you described. In most cases of temporal fascia grafting in rhinoplasty, the graft itself will not dissolve away. The intention is that it is placed to cushion your normal skin so that contour irregularities like you had will be camouflaged away. Hope this helps in your understanding and expectation. 

Fascia grafts are often placed in revision nasal surgery to add a layer to the already thinned skin. It may feel spongy for several months, but usually settles down.

Fascia grafts are an excellent material to camouflage irregular nasal contour - I have used them for years. These grafts may feel soft for a short time post-op. You do not mention when your revision was done, but  the texture will improve over time. These grafts will not dissolve.