OK you might have a chance then. You can try my non professional hillbilly approach that worked on a Tacoma I had with a bit of rust on the rocker panels started by scuff marks getting in and out of the truck and letting dirt sit there I guess, no other rust around it. In other words from the outside, not some hidden inside issue. Anyways goes something like this..
With painters tape mask off a neat square or whatever shape about an inch beyond the damage on all sides. Start with 80 grit sand paper by hand and gently start stripping most of the paint and all of the rust you can. Then switch to around 150 grit and smooth it a little. Get a small can of cold galvanizing compound or a spray can of same from the hardware store and apply an even not too thick coat. Let it dry. Hit it again lightly with the 150 grit and put another coat on. This stuff has zinc like proper hot galvanizing compound and its supposed to neutralize the rust and it does that to some extent IME. I just used the best Tremclad match on top of that on my Toyota. Once you remove the tape ya you could see the "patch" but it looked half assed neatly done and the match was close so it wasn't an eye sore. I used the truck another couple years in a real bad rust environment and nothing changed.
If you go this way and use proper car paint on top just check if it will stick to galvanized. If not Tremclad and others have a primer that does, then you can top coat it with car paint or anything else actually. A body man will shudder reading this, but hey the whole works can be sanded off in a minute and done right later if anyone wants to. Good luck with it JOG
Last edited by Salty303; 04/02/19.
