Tighten Skin

Is it true that , that the only way to tighten tummy skin is surgery?
my stomache is flat but the skin on it ( age) LOL is so loose , I work out and am fit but i dont see the skin tightening, just the muscle tone.. is the only way to tighten my skin a tummy tuck?
From what I’ve read neither situps or crunches will reduce your tummy. I went to the link below to educate myself. Makes sense! Good Luck!
Healthy Skin Care : How to Tighten Loose Skin