I had robot-assisted radical prostatectomy, mine also in August. My understanding is that the internal sphincter is removed in that surgery. (For more on that, see
https://health.ucdavis.edu/urology/specialties/robotic_surgery/prostatectomy_FAQs.html#incontinence )
My surgeon tells me that 3 to 4 sets per day of 10 kegels each (10 seconds contracting followed by 10 seconds relaxing, done ten times, is one set) is about right: more than that, he cautions, can tire the muscle and have an opposite effect -- make things worse.
The best kegel instructions I have found are at
https://prostatecanceruk.org/prosta...prostate-cancer/pelvic-floor-muscle-exercises -- the info there was helpful when I wanted to be sure I was doing it correctly. However, I would echo cmulwee's advice to see a pelvic floor physical therapist, if possible, if things are not going well.
My surgeon (head of the department at a well-known teaching hospital, by the way; he's done over 2,000 of these procedures) also tells me that about 10% of men who undergo the procedure will need surgical intervention to stop the leaking. That's not usually considered, however, for maybe a year after the surgery -- I assume, to allow plenty of time for pelvic floor training and development as well as full healing.
I do three or four sets of kegels per day -- that is, a total of 30 to 40 contractions -- and I have been pleased with my progress. I've been careful to avoid over-taxing the muscle. It might be good for you to try cutting your kegel program back to something like the one I'm using -- maybe even do none for a day or so at first, to let the muscle recover. It could be worth a try. (If you do that, you might keep in mind that any change in the amount of leakage may take time, so patient perseverance, and resisting the idea to push the muscle harder, will probably be important.)
Finally, I would suggest that, if you can, a good purchase would be Dr. Patrick Walsh's book, "Guide to Surviving Prostate Cancer." Dr. Walsh, who developed the open surgery method of prostatectomy, provides a gold mine of information and advice.
Best wishes!