here are some images of skin staph infections-
http://images.google.com/images?q=sk...N&hl=en&tab=wi

More pictures on the next pages at that link.
Do any of those look like what you have?

I don't know if Neosporin type products or any other ointment or alcohol or peroxide applied topically might help...??
hopefully some of our forum nurse members will reply soon too.
I don't have any idea about the Tysabri or infusion implications.
I would look for a urgent care place in the morning , just to get it checked for peace of mind.