Fantastic answers here! B-cells show up in the spinal tap. I did not have a spinal tap because I had lesions in my brain indicative of MS and my symptoms matched those of MS. Plus I was having different problems over a period of about 12 years. They would come and go and docs never knew what was wrong. I had a couple MRIs but they came out clear. I have a new Doc now who questions why I did not have a spinal tap and I told him...cause they got a diagnosis without it and I don't want one now!
Then all of a sudden one day the doc orders an MRI and it was not clear. I had 6 lesion. (thats where the term Multiple comes from in MS)
Its important at this time you write down a sort of history and time span of your symptoms. This will at least get them in your medical records.
I take Betaseron shots just below the skin with a tiny, short needle. It doesn't really hurt, but the reaction site turns purple and red and looks really nasty. I have not had any real sickness after the shot either. I understand your anxiety over this whole process, but please don't panic! If you have MS it may take a completely different course than your father's MS. Its impossible to judge MS by how someone else has it.