Hematoma after breast implant surgery must be drained. This is an infrequent complication of breast augmentation, but is probably the one most physicians fear the most. Plastic surgeons that perform large numbers of augmentation will invariably see and treat patients with this condition -- it happens to all surgeons. Despite the fact that I have developed a technique to perform breast augmentation and lose less than a teaspoon full of blood for the entire operation, I have had 2 or 3 patients with post-operative hematomas that I had to drain.
Hematoma after breast augmentation is one of the contributing factors to capsular contracture and even implant infection and therefore need to be drained to help prevent these complications.
It is hard to second guess your surgeon -- he/she has followed you through this process and has been able to examine you and should have a better idea of what should be done. There are ways to drain fluid collections sterilely and with minimal risk of puncture of the implant. You may want to discuss these options with your surgeon