Why did my breast stay small even after I gained weight?

With a breast augmentation, you will look similar to what you are now but fuller.   There are variations are what size fits your body and what size you like.   The FDA requires women under 22 years of age to use saline implants rather than silicon implants.   

Some women simply have smaller breasts. If you want larger breasts, speak with a surgeon about a breast augmentation but keep in mind that cleavage is dictated by your anatomy since the implants must be centered behind your nipples. My best,
Dr. Sheila Nazarian
@drsheilanazarian on Instagram

The only natural way to get larger breasts is to put on weight. If you want to consider breast implants then you could be a great candidate. You would have to have a consultation with a board certified plastic surgeon in your area. Understand your options: 1) No Surgery – While the benefits of breast augmentation have been mentioned above, there is always the option to NOT have surgery. You should understand what breast augmentation with breast implants can and cannot do for you. While breast augmentation can improve self-esteem and self-confidence, surgery is never an option for trying to fulfill deeper emotional issues.2) Natural Breast Enhancement (fat transfer breast augmentation) – Some doctors offer augmentation using your own fat to add volume and improve breast shape. This procedure can also sometimes be done under local anesthesia vs. general anesthesia and requires less recovery time. 3) Breast Augmentation with Breast Implants – The benefits and procedure details have been listed above.When deciding to have surgery, you should be comfortable with your doctor and his staff members. You should be confident that all your questions have been answered in a manner that you understand. You should be aware of all the normal healing, as well as common, less common, and unusual risks to whatever degree you are comfortable with. (Some patients decline to hear about more serious complications). A more comprehensive list of issues and complications during normal healing as well as a problematic post operative course is available at your request. This information is always provided when you schedule surgery.