How did my boobs not get bigger after under muscle, 450cc, silicone implants?

Dear Philosophical766732,
I understand your concern. However, without a proper assessment, it would be difficult to determine what went wrong. It is best that you visit your plastic surgeon for further assessment or ask for a second opinion. Only after a thorough examination, you can get proper recommendations and advice.
Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

Simply performing a lift without an implant will make the breasts seem smaller because they are more compact. Add an implant to that and your breasts might not seem as large as expected. The implants do, however, provide upper breast fullness

Since you are wearing the same bra as before surgery, you were not wearing the correct size bra either before or after surgery. With 450 cc's, you would have gained up to 3 cups in size.