Had gynecomastia due to low testoterone had surgery on nov16 .havent smoke weed since october.is it possible i could smoke a joint without a problem?

Never again: The gynecomastia was probably due to the "weed" you smoked, not low testosterone. Since it is impossible to totally remove all the breast tissue, you could get a recurrence of the gynecomastia if you go back to smoking the "weed.".

Anything Possible: Anything is possible, but why risk it. Weed is know to lower your testosterone and lower testicular function. Whether the breast enlargement was directly due to the weed, indirectly due to the weed, due to low testoerone, due to higher estrogen level or estrogen intake, or due to obesity, you have take steps to reduce the gynecomastia, why would you do something that might cause it to return?

No: Not a good idea to risk recurrence of the gynecomastia. Avoid the use of marijuana or any other agent known to expose you to the risk of recurrence. Best wishes.