Which treatment or surgery do you suggest for 5 years post op lipo, with irregularity and loose skin on top of my belly button?

Thanks for the question, my suggestion would be to break the scar up and at the same time use plasma energy to tighten the skin, this can be done under local with minimal downtime. I would not know if the results will be perfect but I think you should get improvement

For best results, I recommend a hi definition procedure like a VASER liposuction revision. I use VASER HI DEF with ThermiRF and fat grafting to get the most fat removal, skin tightening, contour and definition. This combination will give you the most toned result. I recommend getting a formal evaluation with a hi definition physique expert. Best, Dr. Emer

See your plastic surgeon for options. Radio frequency treatments may help without any surgery. Also, there may be some peri-umbilical surgical options. 

Hi and welcome to our forum!
I'm sorry that you have experienced this complication of liposuction. You appear to have a constricted scar which can be broken up surgically. Additional fat can also be injected into the area to further improve contour. 
I recommend an evaluation by a board certified plastic surgeon with considerable liposuction experience.
Best wishes!