Did I just stretch the skin and ruin the results?

Thanks for the question. After 6 weeks your surgery area is totally healed and yes you can do gym and also do other activities. I wish you all the best.

certainly if you truly just were stretching and not exercising than you didn't harm anything.  Just a little scaring that you probably tore slightly.  Check with your surgeon before you exercise

I am extremely conservative with my recommendations regarding postop gynecomastia or female breast surgery. My patients will need to avoid exercise, heavy lifting, stretching above the head, or contact sports for 6 weeks, during which time I also require the use of a compression shirt.  Stretching at 18 days is a no-no for me.  You may sheared an area of scar tissue underneath your breast skin where the gland and fat were removed.  If this is also accompanied by significant swelling, then you can be experiencing a hematoma (blood collection) that may need to be drained.  Hopefully, what you experienced was a minor symptom and it will not affect your results. :) 

Thank you for sharing your question. 18 days is still early for any stretching or activity so you may have pulled something. Please see your operating plastic surgeon for a post op appointment to assure all is well. Best,

You are very early post-op and stretching may have pulled on some developing scar tissue. It is hard to say but if you are concerned, see your surgeon.

Probably not, but it is usually a good idea to talk with your surgeon prior to exercise after any procedure.  There are technical issues of what exactly is done at the time of the procedure which will dictate whether a particular activity is safe.  Pain is the bodies way of telling you that you have overdone the activity.  Best to speak with your Surgeon and ask what special precautions you should employ.  My rule of thumb is to start moving about early in small increments, gradually increasing the range of motion over the days and weeks that follow with full return to activities in 4-6 weeks  with some rare exceptions.