Hi there, thanks for including the pictures.
From what I can see (the bubbling of the paint itself), it does look as if the corrosion is originating from within - which means that when you start rubbing down the panel, you will more than likely start finding holes.
You can still repair this (I would, if it were me), but as I previously mentioned, it will need to be tackled from both sides, and more than likely, filler will be needed to provide a smooth and stable base for repainting.
I would reiterate that this will probably not provide a long-lasting (i.e. more than a year or so) repair, before it will need some rework, but its worth doing, as it may last longer if done well.
The entire job will take approximately one weekend to include rubbing down/filling/sanding/priming/painting. I would start the job on a Friday night, leaving the filler to harden overnight, then spend Saturday sanding & priming, getting the final top coats on for Saturday night, then by Sunday lunchtime, its fixed - the polishing up would be left until Wednesday (to be on the safe side).
Hope that helps you.
All the best, and again - any questions? Just ask away.
Let me know how you get on.