MS or B12 defiecency

New diagnosis and before diagnosis
1

Hi i am new to this forum I have recently been diagnosed with Ms based solely on MRI scans. There was an increase of two lesions on brain mris taken 3 months apart. 3 lesions on spinal mri but no change on follow up 3 months later Have not had lp. Had bloods done came back with a b12 level of 90 but neurologist ruled out this being the cause of the lesions and said it was only slightly low. However i have my doubts from research level of 90 is really low. Only symptom i have is very slight numbness in left arm amd had severe tiredness before going on b12 supplements. Feel fit and healthy. Neurologist wants me to start gileyna but i am thinkin of seeking a second opinion. I am 27yo female. Has anyone any thoughts on the above or had a similar experience Many thanks in advance