It's important to not assume you have Multiple Sclerosis until you have an actual diagnosis. There is no single test, by it's self, that will give a definite diagnosis of MS. Lesions found on MRI can have many causes, sometimes it's MS and sometimes it's not. When you see the Neurologist you will probably have other testing done as well as a Neurological exam/evaluation.
A relapse (exacerbation, attack, flare-up) all mean the same thing; old and/or new symptoms lasting continuously for more than 24 hours. Exacerbations can last weeks with recovery taking longer. It's not a new exacerbation unless it's separated from the previous one by 30 days.
Each person experiences exacerbations differently and depends on what part of the Central Nervous System is affected. For this reason it's impossible to compare exacerbations.
I don't mind explaining what my exacerbations are like but I don't think it would be helpful for you especially when you don't know if you have MS. If you still want to know just ask I will tell you
When is your appointment with the Neurologist?
Diagnosed with Multiple Sclerosis in 1985
PTSD diagnosed Feb 2004 (PTSD since age 2), Anxiety/Panic attacks secondary to PTSD.