My lutino was clipped when I got him and so he took a few nasty spills. He also ended up with a couple bloody tail feathers. As far as I can tell it's basically harmless as long as it's a very small amount and not continuing to bleed. Maybe it's self inflicted. Keep an eye out.
My bird didn't have nearly that much blood though.
I think a good avian vet is your first port of call, if you haven't taken him there already.
I have not dealt with this issue, but I attended a talk by Pamela Clark last year and was very impressed by her thorough approach to the subject. Here is a link to her website: http://pamelaclarkonline.com/uploads/Fe ... artOne.pdf