Welllll what you do is you wait...and keep exercising...and age and genetics and sun exposure will all settle you out to "your" skin a year or two after you reached goal.

If you regain and do this again at 35, the skin will look worse...at 40, worse still, and so on. If you hate it, use it as your motivation to never go back to carbs.
So the year or two has passed and you still don't look like magazine models? The truth is, neither do they. Those photos are airbrushed. The little bit of extra wrinkling or stretch marks you might have are now your marks of being a warrior; like an Amazon with only one breast, you've earned those scars through a tough battle. Be proud of them.

Whenever I start to mope about the tiny matter of my imperfect skin, Fate tends to send me someone delightful with burn scars or skin cancer or missing legs or the like...and I realize what a small, small matter my focus on my wrinkled thighs is--just cosmetic stuff, and no one who matters will judge you for that.