I had a tummy tuck and now I want the gastric sleeve. Do you think that procedure will mess up the results of my TT?

The good news is that having a gastric sleeve after a tummy tuck doesn’t necessarily undo your previous results, but there are a few important things to consider. Sleeve gastrectomy typically leads to significant weight loss, and depending on how much weight you lose, you may notice some changes in your abdominal area. Even though the excess skin was removed during your tummy tuck, further weight loss can still lead to skin laxity or a change in contour, especially if your weight loss is dramatic or your skin has less elasticity.
That said, the gastric sleeve is done laparoscopically, which means small incisions, often placed above or around the belly button—areas that may or may not overlap with your tummy tuck scars. A skilled bariatric surgeon will be careful with incision placement and will work around any previous surgical sites to minimize any disruption.
If your tummy tuck was fairly recent, your surgeon may advise you to wait until you're fully healed before proceeding with sleeve surgery. But if it’s been a while, and your health and BMI suggest bariatric surgery would benefit you, it’s definitely still an option. Just be sure to talk it over with both your bariatric and plastic surgeon so they can coordinate your care and manage your expectations about potential changes in appearance as you lose weight.

Obviously Gastric Sleeve Surgery is to achieve significant weight loss. Most people will have some sort of excess skin after major weight loss, surgical or non-surgical...
Worst scenario, you will need a re-do tummy tuck. But there is a good change that since you already had a TT, the cosmetic outcome will still reamain. So you may not need another tummy tuck!!!
It all depend on your gene, how much you are going to lose and your definition of "Mess up the results".

Hello
Thanks for your time and question.What I can tell you is everyone has her own body shape, both before and after weight loss. Some people have more loose skin after weight loss,  It's exceedingly rare to have no loose skin after massive weight loss--and it does not matter how slowly or quickly you lose weight. The skin damage is done with the weight gain, not the weight loss. Weight loss just unmasks it. So I cannot ensure you it will not affect your previous tummy tuck or that you wont need another one. so what I would recommend you is to visit a certified plastic surgeon to discuss the best option for you 
Good luck in this journey, blessings .!
Dr. Pablo