Swelling after gynecomastia surgery
Swelling after surgery can be consistent or spontaneous for up to nine weeks. Considering yours happened after massaging it is likely that a pocket of blood was disturbed and less likely that you caused permanent damage to the area. It is good to hear that the swelling has gone down, but if it persists at all or you have more concerns, it is best to have your surgeon examine you for proper evaluation
What causes this sudden swelling?
I am sorry about the setback you experience; based on your description, is most likely that you had some bleeding associated with the aggressive massage. Fortunately, it sounds like the fluid accumulation it is resorbing. Best wishes.
Swelling after gynecomastia
The sequence you explain makes it seem like this is probably a small hematoma, or collection of blood. This could grow to large proportions, but it sounds like yours is fairly small. When their large, we usually drain them to avoid slow healing. When they're small, they will often resolve on their own. Sometimes they can be trained with a needle when it turns into more of a liquid. You should definitely see your plastic surgeon so he can evaluate the situation and give you guidance.