I'm with Wayne here Daniel. If you can, try to get the paint out of the panel lines and control surface joints first, then continue sanding. OK, you'll still have to go back to the panel lines, but doing it first will remove the worst before they're clogged with sanding dust etc.
When you've finished sanding, give the whole model a polish with 'T-Cut'or similar, and it should look smooth again, with any sanding scratches polished out. Before re-painting, give it a thin, even coat of primer, probably a light grey enamel, and let it dry for a good 12 hours at least before doing anymore.
Don't worry about the fabbric detail being lost; on the real aircraft it isn't visible, even close up, and the 'ribs' on most models are nearly always overdone anyway.
It cetainly looks like it was celluloe thinner that caused the problem - so put it away!