Either implants or fat grafting can be used to help correct your asymmetry. An in person exam with a PS is your best next step.
Thank you for your question. This is a surprisingly common problem for women. Surgery is never the only option. Of course you can wear an external prosthesis in a bra, similar to what women who have had a mastectomy wear. I assume you already do something like that, however. That leaves surgery as the next option. From your picture it appears you would need the right breast tightened with a lift, and an implant placed on the left to balance the size. Another option would be to place different sized implants in. The best thing for you to do is see a board certified plastic surgeon to discuss your options. Surgery is very safe nowadays, but even so it is normal to be nervous about having it done. Good luck!
Your breast asymmetry is certainly only going to be improved by surgery. Whether that would be by breast implants or fat grafting is a matter for further discussion.
From your photos placing different size implants would good you better symmetry. It is a good option to help your uneven breast.
Based on your picture, it appears that surgery would be the only way to help achieve better symmetry. Using different sized implants on each side would help balance the breasts out and allow you to have better symmetry. It is normal to be nervous about undergoing any surgery. However, this is a very straight forward procedure with a very low complication rate. The best thing to do is to go for a few consultations with board certified plastic surgeons and see what will work best for you. I hope this helps.
Implants will probably be the easiest way to correct your difference in one surgery. However, fat transfers could also be an options. I would suggest meeting with a board certified plastic surgeon and discussing all your options.