I can see why you have lingering doubts about the white matter lesions. First your doc said you're too young for them and then he said they happen to older people like you. ???? I suspect he "read up" on the subject while he got the second MRI and found that his first assessment was wrong. No doctor can keep all the knowledge in his head and keep up with all the new stuff.
Yes, beginning in about our 40's a lot of us begin to acquire little white matter brain "divets." They are often found incidentally when a scan is done for some other purpose. They can occur from migraine headaches, high blood pressure, "aging," whatever. They also can be evidence of a neurologic disease, but that association would be made when there are physical signs and symptoms of neurologic problems. A single episode of hand tingling could be a sign of MS, but that's rather like looking for a boa constrictor when it is probably a little garter snake.
Depending on your own feelings you could so a few things. The first thing I think you should do is get a copy of the two MRI reports for yourself. I recommend this to anyone who has imaging or lab work.
Second, the stress of all of this is enough to get anyone tense. Treat yourself to a neck and back massage. Learn some loosening and stretching exercises for the neck and do them a couple times a day - gently. Learn about carpal tunnel and the exercises felt to prevent it. Do those. If the tingling comes back or other things happen, then seek help - I would request a neuro eval if other stuff pops up.
If you really are persitently stressed about the MRI findings, then ask for a neuro eval now and set you mind at ease.
Good luck, Quix
Thank you for the information. This has put me more at ease.