Why is my abdomen area hard and feel hot 17 days after tummy tuck and lipo?

It's a great question. If you have concerns, reach out to your surgeon for specific advice. It is common for the tissue on the lower tummy to be firm after a tummy tuck procedure. It can take several months for this area of swelling to improve. However, it's important to make sure that the swelling isn't coming from a fluid collection under the skin. Only your surgeon can determine whether collection of fluid is present. Congratulations on your recent procedure.

You are still very early in the healing stage it is normal to be swollen and you will continue to be for a few more months just be patient and continue to follow up with your PS.

suggests infection or inflammation and you must see your surgeon.  Hardness can come from many things but any concerns you have should be addressed with your surgeon.  And your surgeon is obligated to be there for you during the recovery period so see your surgeon.