All of your MRI's have come back negative for MS. Your symptoms are not indicative of MS. A doctor has told you to undergo testing for migraines, which you haven't done, and now a doctor (the same one? a different one?) has suggested your problems might be allergies (or at least, skin sensitivies), but you're not following up on that. How many neuros, or MS specialists will you see before you're convinced that maybe you don't have MS?
A lumbar puncture is an invasive procedure, not likely to be conducted unless there is some evidence that there is some disorder (not necessarily MS, but something ) that might show up in the spinal fluid. Not all diseases show up there. Apparently the doctor isn't convinced that there is enough evidence to warrant that, so that's why she's not considering it.
You're dismayed because the doctor might "think you're mental". She does think you're suffering from anxiety (which is why she prescribed the Atarax)-- which is expected, because you're convinced you have a disease for which there is very little evidence, and when doctors suggest you be tested for things for which there is some evidence (migraines, allergies), you're choosing to not follow up, but instead pursue your theory that you have MS.
I've nothing more to offer you. I'm sorry you're still feeling all these sensations. I hope some day you'll get to the bottom of what is causing the difficulties.
...I am not a doctor, nor health professional, and don't pretend to be one, here.....