Is it normal to have wavy lumpy saggy thighs 5 weeks after liposuction? (Photo)

I really don't think that age is the defining factor determining whether you will have sagging skin between your thighs following liposuction.  It is more the amount of skin there is, how much fat there is to remove, and the surgical technique.  Inner thigh liposuction is difficult because the skin in this area is thin and typically loose.  It is even more difficult in a thin person like yourself because the margin of error is literally narrowed... Less fat, more chance for too much fat removal leading to indentation.  There appears to be obliquely oriented indentations on each inner thigh which may be a line that has been suctioned more than the surrounding areas.  This will probably improve to a certain degree.  If it doesn't, a technique called "Safe Lipo" could help.  I would do this in the office under local anesthesia with oral sedation.

There are definitely some options for skin tightening in these areas, but I would wait until the lipo has reached it's final result, at about 6 months.  You may find that some of this still improves on its own.

I suggest massage and RF treatments at this time.  If you do not see improvement by 8-12 weeks then you will need a revision with fat transfer.  Please post initial photos for us to compare.  Best, Dr. Emer.