1 month post op, should I be worried about gaining a little weight after Gynecomastia surgery?

Most likely you are experiencing a lot #swelling and inflammation. Also, if you have been following your post-op instructions, you may have not been as active as you were prior to the procedure. This may also contribute some weight gain depending on diet and caloric intake. Usually 1 week after #gynecomastia surgery you can begin taking moderate walks or ride a stationary bike. Strenuous workouts or aerobic #exercise can begin around 4 weeks post-op. I suggest you get approval from your doctor before you begin any physical activity and workout regimens. It important to prevent any damage to the surgical sites as you are healing. This will decrease your chance of requiring #revision procedures in the future. The best advice is to be patient as it is still very early in your post-operative #healing. If you have any concerns about #healing, its best to ask questions of your surgeon or their nursing staff.

Your results may be negatively affected with weight gain, but I think you should be able to reverse this with proper exercise and diet once you've been given the green light by your surgeon.

            Weight
fluctuations after cosmetic surgery are common. There is almost always a 3-4
week window of time after surgery when you are restricted in your activities in
order to allow the early phases of healing to happen. Unfortunately, a lot of
patients get out of the habit of exercising and dieting and it can be hard to
get back on track. A little bit of increase in weight shouldn’t result in any
long term change in your outcome, but you need to recognize what is going on,
get back to the gym and stop this from becoming a progressive trend. Even if
you are not yet feeling up to your normal workout, at least get out and walk.
Start slow and then progressively more aggressive until you are back on track.

            The
tissue that was removed with the surgery is gone forever, but the fat that is
still there (and there is always some there) will swell if you gain weight or
contract when you lose it. It’s up to you to maintain the results your plastic
surgeon achieved for you in surgery. 

It is common to gain a little weight after surgery because of inactivity and possibly from swelling. Once you have healed and can go back to working out, more than likely the weight will come off with good habits.

A small weight gain should not have a negative impact on your gynecomastia surgery.  It sounds like you are headed in the right direction.