Used enclosed trailer

[CamarosRus]

My 2004 Pace Shadow GT (Top of the Line) 20'10K GVW has the Glued On Side Skin (NO screwed fasteners)

Up near the top there are small areas of rust. Ive been told this is because steel frame that outside skin is glued too
wasnt painted and my skin is rusting from inside out

1) Anybody else know what I'm trying to point out

2) Anybody have a solution or "fix"

3) NO, Im not going to remove outside skin at this time

Thanks for your helpful suggestions