What? No, hi Chena, how have you been these days? LOL ;)
The questions you've posed have no doubt been answered time and time again. In my honest opinion, the truth is that if God presented Himself in your living room tonight and told you that He created the plant, that we call marijuana, and He created it for medicinal purposes and you were wrong to deny the sick from using it, you'd argue with Him until Hell froze over that He was wrong, and you are right.
How's that for a run-on sentence? :)
Given past experiences with drugs and those who offer them, we've decided that the FDA is a good clearing agency. They're not perfect, but they're better than nothing.
If indeed God created created marijuana for medicinal purposes, it will be verified by that agency. HE can take it up with them. I see no reason whatsoever to make an exception for marijuana.