LLD, bad habits need to be replaced by good ones. The first thing that you need is patience. The second thing you need is a good teacher. What you describe is not "self-help" although a lot of us have great fun in suggesting all sorts of things for players we have never met. Every embouchure is individual. Many times, simple exercizes like buzzing and pedal tones can firm up flabby muscles. Whether this is the "right" thing for you is difficult to say. It is dangerous to think about changing ANYTHING drastically when you are in the middle of projects. A change of embouchure can wipe decent playing out for 6 months or more. I can only recommend finding a good teacher. Tell us what general area you are in. Maybe there is a qualified TMer not far away!