Replying to Rust Prevention

My car is starting to grow some body rust unfortunately and has some crusty pieces underneath as well. For Michigan standards its doing alright but I don't want it to start going downhill to quickly. For parts underneath I ground off the flaky bits and sprayed rust converter paint from the hardware store on and covered any exposed metal with it as well. Not sure how to go about the body rust yet. Starting to see on the rear wheel wells, drivers side moee than passenger side. Anyone got tips other than move out of Michigan?