Hi ! Good afternoon. I am Dr shareef answering your query. Many children specially adolescence boys do get this kind of swelling in one or both the peri aereolar tissues below the nipple due to hormonal imbalance which gets ok in due course. In your son s case this has occurred a little earlier. Please do not get worried, and you can also explain gently if needed to your son that it is a nomal physiology which will be ok very soon. Just to inform you and not to frighten you, this condition (known as gynaecomazia) may persist in some boys into their adulthood, and in that case some kind of plastic surgery for cosmetic reasons only might be indicated. I hope this information would help you in discussing with your family physician/treating doctor in further management of this problem. Please do not hesitate to ask in case of any further doubts. Thanks for choosing health care magic to clear doubts on your health problems. Wishing you an early recovery. Dr Shareef.