These can often be papillomas or warts. Since this one is bleeding, you will probably have to have it removed by the vet.
For the rest of the weekend, you should clean it well with peroxide and then cover it tightly with a bandaid after you dry it. This will keep it from bleeding and bumping into things.
You will want to see the vet on Monday to have a needle aspiration done (to rule out a tumor, more than a papilloma) and to discuss your options.
Let me know if you still have questions.