Semen is usually much worse for blood than urine. For first few days, semen can look like tomato ketchup, and after that, brown sauce. I've had a couple of callers on a helpline call up having not ejaculated for months after a biopsy, and their semen was black by then.
It's a good idea to get the blood out of the prostate, because if the iron from the red blood cells is left there, being magnetic (once it's gone brown), it will reduce the quality of any subsequent prostate MRI you might need.