It depends where on the trailer and what panels it is in. Post some pictures when you can. If it's not in one of the end cap segments (the radius panels front and back) then with the right tools you can replace that panel (drilling out old rivets, and either installing with olympic rivets (a form of pop rivet with a solid core that you use an expensive tool called a rivet shaver to shape the head to look like a bucked (hammered) rivet.) Lots of folks on here have done panel replacements and have good tutorials/documentation of their efforts. It's worth some time looking around on the forums with the search tool and see what other folks have done, ask them questions etc.