Worried about the little to no cleavage, is it swelling or symmastia? (Photos)

Thank you for sharing your question and photographs.  I see your area of concern but there appears to be a clear separation between your breasts, making synmastia less likely.  Additionally, due to swelling in your breast tissue your implants are being held high against your chest.  As your results mature you will see development of underboob, but you need to allow yourself 6+ months of recovery.  Hope this helps.

HiLooks like swelling. Need to wait a full three months to see how it resolves. Regular visits with your surgeon and continued icing will be beneficial for you.

Hello, based on the photos there seems to be a defined gap between the breasts.  If you notice a raised web or bridge of skin between the breasts, this is typical of synmastia.