Neurologist?

I'm going to the neurologist soon (December 9th) due to frequent migraines and I'm really worried! I'm not familiar with this doctor and I'm not familiar with their practice. Could someone please tell me what's going to happen? Will they take blood, will they just write me a new prescription? I know it probably varies for many different doctors but could you please share your experience with me so that I can get a sense of what may happen?