*are you sure they came from his/her ears and not another area on the body?

*are you sure it wasn't something s/he ate & it somehow got smeared? (When my rabbit eats strawberries, she often gets it ALLLLLL over her--and it looks very much like blood.)

My advice would be to check the rattie's body over and make sure there are no open wounds that need immediate attention. Personally, (assuming the bloody area is/was small and only happened that once) I would keep a watchful eye on the little one and wait a day or so to see how things went.

Good luck ~ Please keep us posted.

Also remember that sometimes "small" incidents are worth a trip to the vet, just for the peace of mind it brings!