I had a bad case of optic neuritis in my eye a year ago w/ ms. I notice that pupil is almost always dilated larger still. Normal? Or cause for concern

Yes. It is not that unusual to have a persistent pupillary abnormality following optic neuritis. Usually it is only detectable by someone performing a "swinging flashlight test" (usually an eye doctor) but sometimes can be seen by the patient or family member in normal light.
Dilated pupil. Presumably what happened is that you sustained optic nerve damage & the nerve is not transmitting enough light data to tell the pupil to contract more. The "afferent limb" of the "direct" light reflex is damaged. If a light shined in your other eye causes the dilated pupil to contract, then the "consensual" light reflex is intact. That's called a Marcus-Gunn pupil.
Not surprising. Your eye likely still displays what is called an afferent pupillary defect, and dilates with light exposure. Do not be alarmed. But, if you have a diagnosis of MS, why do you not list an MS disease modifying agent, which would be critical in controlling future issues? Do you not have a neurologist who focuses in MS??