Completed 8 times bcg. little blood in urine even after 3 days of bcg completion. is it a danger sign?

No: Not unusual for bcg to cause both visible blood in urine and/or bladder irritation (urgency, frequency, burning) especially after repeated doses (6-8 treatments) as inflammation of the bladder is one of the ways that bcg works. Blood can sometimes also be related to a uti. If not otherwise very symptomatic, increase oral fluids and monitor. If symptoms or bleeding worsen, contact your urologist.