Is it normal to have trouble having an orgasm after Tummy Tuck & Liposuction of the mons pubis? Is it permanent?

Tummy tuck and liposuction will produce surgical swelling.  This swelling can settle into the clitoral/clitoral hood area and alter sensation and arousal.  As this swelling subsides your ability to achieve your typical organism will return. 

There are a number of reasons why major surgery can affect sexual function. However, with resolution of the physiologic as well as psychologic postoperative issues this should resolve.

Swelling can account for your changes in sensation.  I would expect this to improve over the next 3  - 6 months.  

 After tummy tucks, the pubic area can be elevated and therefore stimulation is altered.  Eventually, most women figure out how to adjust for this and normal sexual function returns once the swelling and healing are complete.  If problems persist, you may want to discuss this with your gynecologist. 

I guess it depends how long ago your surgery was.  There may very well be residual swelling that is affecting the area.  It would be very unusual for a TT or lipo of the mons area to permanently affect one's ability to have an orgasm.  Maybe just needs a little tincture of time.