I googled this information and on the Michigan Medical Marihuana Program it shows step by step what you need to do to obtain your Michigan Medical MJ card. Seems Michigan requires you to have your records from your PCP with the diagnosis then any physician licensed to practice in Michigan can give you a card to obtain cannabis provided you meet the specifications stated. Good luck on getting your card so you can have options in your own treatment or get active to change the laws.
Each state has its own rules and hoops to jump through. Here are the one's for Michigan.