How long does it take for the skin to attach back to the stomach wall after Tummy Tuck and muscle repair?

After about 8 weeks, I let my patients start some exercise.  It takes about that long for the skin to stick back to the abdominal wall.   The swelling in the tissues can take 6 months to go away.   The compression garment helps with the swelling, not the sticking of the skin to the abdominal wall.

I don't think your swelling is related to the tissue attaching back together, but rather is normal swelling seen after a tummy tuck because the lymphatic drainage in your tissue has not completely reestablished itself. It may take 4 to 6 months for you to stop having swelling, and I have seen it take up to 12 months in some people.

First thing is to make sure there is no
seroma. If you have no seroma, then it is very unlikely you would develop one
at 7 weeks; they form after taking the drains out. However, you can expect
on-and-off swelling of the lower stomach for months (even up to a year postop)
until the lymphatic drainage re-establishes normal flow. Until then, experiment
with which garment gives you the best compression, yet is the most comfortable
to wear. Hang in there, this will pass!