Will Sliding Genioplasty Tighten Up the Neck Area? Or Will I Need Neck Lipo?

My chin is small especially in vertical height and I plan to have a sliding genioplasty in the near future. I am 20 years old, female, and very fit, but my neck from a side view looks sort of loose, like a double chin. I am not even close to being overweight. When I have my sliding genioplasty, will it pull this skin and tighten up the area or should I also plan to have lipo there? Thank you for your time and answers!!