These can often be papillomas or warts. They are manifestations of a viral illness.
You will want to see the vet as soon as you can to have a needle aspiration done (to rule out a tumor or cancerous lesion, more than a papilloma) and to discuss your options.
If they are bleeding when something comes in contact, your vet will probably want to remove them. Dogs get papillomas for much the same reasons that people do. In some cases, they can be cancerous so I would suggest that you see the vet for a fine needle aspiration to rule this out. At this visit, you can discuss removal.
It's a pretty straightforward procedure.
The problem with these things is that they seem to grow overnight.
Let me know if you still have questions.