I can't answer about whether it causes MS, but I can certainly say it does seem to cause symptoms that mimic it. Tongue tingling was one of my symptoms that drove me to the doctor. My PCP immediately sent me for a brain scan, but fortunately there were no lesions and a follow-up visit with specialists determined that my symptoms were not clustering enough to suggest MS.
It is terribly scary, though. I hope you can have the Mirena removed ASAP. I have had lingering side effects, but nowhere near what I encountered toward the end when I had it in. Good luck