Can I use a low set heating pad to move edema in the lower ab and pubic region? (photo)

Best to run these types of questions by your plastic surgeon. I do not know of any science that shows that the use of a heating pad will necessarily help with the drainage of fluid.   I personally advise my patients not to use heat or ice directly on surgical sites, for fear that the relatively numb skin can be injured. Best wishes.

I don't suggest to do that your swelling would decrease with time, Heat pads could injury the skin without you even feel it, Follow your surgeons advise he/she would know you best. 

As before these post operative concerns and issues are specific to your own surgery, therefore you NEED to see your surgeon for their advise and recommendations. Not some over the internet surgeon who does not really know your surgery or post op course..//