First of all, do not worry. You didn't hurt him. Sometimes the nubs refuse to stop bleeding after the horny sheath is removed. You did all the right things.
Coincidentally, I have a Cream Legbar roo who had his spurs removed over a week ago, and I had the very same problem. Then a few days later, he was goofing around and he banged one of the spurs and the bleeding began all over again. Blood everywhere. A bloody mess, pardon the pun.
I used corn starch to stop the bleeding, but I decided to bandage the spurs with vet wrap to protect them from getting knocked and damaged again. I sprayed with Vetericyn and put some triple antibiotic ointment, wrapped a small square of Telfa pad around the spur then put on the vet wrap. It's such wonderful stuff because it stays put without tape, which would only come undone. Roosters are not sedentary creatures in case you haven't noticed.
I remove the bandages every two or three days, check, clean, and bandage again if the spurs are still moist. Some spurs harden in just a few hours after removal while others bleed and take a few weeks to harden. It depends on the individual. But relax in knowing your rooster's spurs will heal and harden eventually.
I don't believe I've ever heard of a case where spurs have become infected. If they have, it's extremely rare.