I feel that you should finish the course of antibiotics. I would be uncomfortable that I would be creating superbugs, unless I did complete it. I worry about such things though.
You won't have to worry about mutating bacteria when you're taking MMS. MMS destroys each cell immediately; as well as destroying itself in the process.
It should not be a problem to take both at the same time. Well, maybe an hour apart. They use different processes to kill the bacteria.
"If stupidity got us into this mess, then why can't it get us out?" —Will Rogers