First of all, I am sorry to hear this happened to you. I had a similar experience earlier this summer with a pit bull mix

How bad is the bite? Was it a full double-tap bite or more of a broken skin problem? If it is the former then you should at least have your doctor clean it well, I had quite a problem with getting mind to heal.

I've decided against spray since it doesn't sound all that effective and it matters which way the wind blows. What I need to get is an Airzound...

Don't let this put you off, I must admit that I am more nervous than I once was about dogs, but I still ride. Now, however, when I see someone walking an unleashed dog I am more likely to just stop my bike and let them get by before continuing.