Neck lift with incomplete results - Z-plasty or should I stop & play it safe? (Photo)

I had a deep plane face and neck lift which looks great except for loose neck skin on one side. My surgeon wants to do a zplasty in a few months to address this. I’m concerned about the scar and also what else could go wrong. I did not expect the first surgery to be unsuccessful. Why might that have happened? I followed all the recovery protocols and am a healthy, fit and active 70 year old woman. Is it worth it to have the Z plasty or should I stop and play it safe?