How to Tighten or Smoothen Crepey Skin After Lipo?

The only way to dramatically tighten the skin on your thighs is with a thigh lift. However you should consider the benefits of the procedure and if they outweigh the cons, which is scarring.

Your problem is one of the main problems that we face in plastic surgery:
If we knew how to tighten skin, we wouldn't have to perform face lifts, breast lifts, tummy tucks, etc.
Your liposuction didn't cause the problem, it just possibly made it more noticeable. Your problem is loose skin which has been made worse by extensive sun exposure, aging, (?possible smoking, weight gain and loss). We can't have taut smooth skin when we are 70 and you are simply mid-way from 10 t0 70.
It sounds as if you have tried every conventional technology that claims to tighten the skin. On a scale of 1-10 these devices generally produce a 1-2 result. If that is the severity of your problem, then these are excellent options. If your laxity is more advanced then these interventions will fail to delever any significant effect.
At this point in time your best option for correction is a thigh lift. However, the vast majority of patients are put off by the scars and it remains an unpopular procedure except for those poaitents with markedy severe skin laxity..
If this is sufficiently disturbing to you, you may want to consider a consultation for a thigh lift. You should be prepared for the scars.

I wouldn't call that ruined at all. You have great legs for a 30 year old, much less a 40 year old! I use the Accent, which I know you tried, for slightly loose legs, usually about 6 sessions, for the loose skin in this area. I have heard some of my patients report that Thermage "made it worse", so maybe not that. If you think you are a little wrinkly from the old sun damage, then do something for your skin, like a fractionated laser.