When you have surgery they cut away the part of the urethra that passes through the prostate, and sew the two ends together (thus the need for the catheter). It is a wound that has to heal. Scars form, scabs form and fall off over time. Bits of suture dissolve and fall out. There will be lots of little garbage and drops of blood over the weeks post-surgery.
If it continues, is painful, or you want to know about
it, call the surgeon and ask questions.
I developed several urinary tract infections in the several months after surgery, and passed a lot of excess goo and gunk, as the sutures finally healed up.
I was told to use waterproof bandages over the sutures and not get them wet (i.e. shower only, no baths) until a number of weeks after the surgery. Then I was to pat them with a soapy washcloth (NEVER to rub/scrub) and to rinse by letting water run down from above them (NEVER pointing the shower spray directly at them. At a later checkup, he had a look, and said "back to normal bathing", and we were done with that challenge.
Moderator - Prostate Cancer(Not a medical professional)
My adjuvant IGRT journey (2010) - www.healingwell.com/community/default.aspx?f=35&m=1756808
HT (Lupron) 6-mo injection 9/12;Prolia 6-mo inj 12/12, 06/13