There is definitely an interesting question here, especially without knowing the exact length of time since your procedure and what specific procedure you went through. Following surgery, your incisions will go through a maturation process. For the first few months they will be red and possibly raised and/or firm. As the scar matures, after 6-12 months, it becomes soft, pale, flat, and much less noticeable. You may experience numbness, tingling, burning, “crawling”, or other peculiar sensations around the surgical area. This is a result of the healing of tiny fibers which are trapped in the incision site. These symptoms will disappear. Some people are prone to keloids, which is an abnormal scar that becomes prominent. There is always a chance that if you are still early in the healing process that your hormones or other internal response to masturbation are simply affecting swelling or tissue tightening. If you find your self uncomfortable or concerned you should likely visit your surgeon in person to have the area evaluated and make sure that healing is going well. Good luck!