Does genioplasty and maxilla Downgraft stretch out the skin? (Photos)

I'm getting a pretty big maxilla Downgraft cause my teeth don't show at all even when I smile (doctor said probably 7-10mm) and a sliding genioplasty to increase my chin length. Can the Downgraft make the face longer if I wanted increased facial height? Also will my chin being lengthened also kind of stretch out my skin so that it is a little more taut? I know it's kind of unconventional to want a longer face but it's what I personally like.