As has been mentioned in other responses, photos would be very useful. You have however qiven a fairly good description of what might be a type of breast deformity that is referred to a tuberous. Treatment of breast asymmetry various widely and will depend on what size breasts you are desiring. At 18 there will be little additional change in the contour shape of the breasts, but with changes in weight, future pregnancies the sizes of the breast can vary and that difference will be unpredictable, so you will need to take into consideration the very high possibility of needing revisions in the future.