Lots of healing to go one week after gynecomastia surgery.
It sounds as though you had a combination of excision and liposuction for treatment of gynecomastia. If this is the case you can expect significant improvement over the ensuing weeks.
Swelling 1 week after gynecomastia surgery
At 1 week you certainly have a significant amount of residual swelling. You should see a dramatic reduction in swelling over the next 6 weeks, but it may be 8 to 12 months before you would see your "final" result. In addition, your skin will retract over this time period, improving your shape. Be patient, and contact your Plastic Surgeon if you have concerns about increased or asymmetric swelling, as this would not be considered normal at this point.
Appearance following surgery for large gynecomastia
If your physician removed 2 kg of fat and also breast tissue, at this point you should have a lot of swelling that will take a few weeks to resolve. Be patient and I believe that you will get a good result.