Can another doctors breast reduction be fixed?
Yes, assymetry of the breasts following a breast reduction can be improved. The procedure would either be additional tissue being removed from the larger breast or a small implant on the breast that is smaller if you wish to be more the size of the larger breast. I would suggest you get another consultation and discuss your concerns.
If the difference is really remarkable, most doctors would want to revise it to preserve their reputations. A small revision fee is not unreasonable but if your doctor is asking for a full fee, I would have issue with that as a patient myself. That being said, now you need to decide on what you like better and pursue either enlarging the smaller one or reducing the larger one and there are different ways to accomplish this. Revisions can be done.