Definitely bring it up to your doctor. They may refer you to a neurologist. MRIs, even in healthy individuals, will change over time. Some changers are innocuous, some indicate a problem.
They may order new MRIs to compare to your previous ones. A full neurological exam would also give insight into what you may be dealing with. It's possible it's something structural, as opposed to something neurological, for example.
In your shoes, I'd just make sure I had my new issue and questions written down for your appointment. It's easy to forget once you're in the room. In the mean time, don't overload on googling. You have an appointment in one week which is not long to wait, even if it doesn't feel that way!
I was diagnosed 2008 with SLE and just diagnosed with MS. I have been having numbness in random places for years but blamed it on my SLE. Apparently that's not really a symptom among the many many symptoms of SLE. My face would go numb and I would think I was gonna have bell's palsy but never did. Half my leg,foot,arm,hand,etc. would tingle and/or fall asleep. I had a baby in June and shortly after my entire right side went numb and had severe weakness in left side. Lasted about 3 weeks. I could barely walk. Got MRI of brain and had lesions. I didn't do anything about it and 4 months later had another severe episode like that. Off to a neuro. More MRI's of brain, c spine, and T spine. All with lesions. So here I am trying deal and get through meds while nursing. My point is, I would defeinitly ask for a neuro referral or even just order an MRI. It can't hurt and it's good to catch it early so I'm told.
You might ask your Primary Care doctor to do a neurological exam. That is reflexes and such. If it is abnormal then you see a neurologist. If it is normal then it would not be MS. My PCP did a neurological exam on me in 2007. She immediately sent me to a neurologist. A neuro exam shows exactly where you have damage in the Central Nervous System.