Can Laser Lipo to Stomach Cause a Hernia?

I like to use safe methods that work. While I DO use Power Assisted Liposuction and VASER, I have yet to be convinced that Laser Lipo is equally safe and I do not use. But, despite NOT being a fan of Laser Lipo I can categorically tell you that Laser Lipo does NOT cause ventral or umbilical hernias. Your surgeon is right and she does not need to own up to anything she has not done.
While, depending on her training, she could possibly fix this hernia, the repair may not be as good as good as one performed by a general surgeon who repairs such hernias weekly.

Your plastic surgeon is right. You had the hernia before but it was covered by the fat and now it is more noticeable. The only issue is that your doctor should have noticed it before surgery when he or she examined you. Most board certified plastic surgeons are also have finished general surgery training and should be able to repair hernias.

Both could be true. You could have had a hernia in that area which became "more visible" after liposuction. This would be more likely if it was noticed by you after a month or so but there also could have been a tear of the fascia in that area to produce a protruberance now. Really difficult to say. If you have had children, then the former may be more likely.