Even though my son has lost a lot of weight, gynecomastia is suspected.

Hello. These days, maybe because of my eating habits, my children are also very serious about weight control. My son has gained a lot of weight rapidly, so we are exercising together. However, even though my son has lost a lot of weight, I suspect gynecomastia. My son has mentioned it, and from what I see, his chest feels very protruding. Should I go to the hospital quickly for a consultation? I'm worried.