There is no really good way to repair aluminum siding without taking it down all the way to the affected panel and reinstalling it. If you have a replacement panel or panels, you can cut the last undamaged panel and nail it to the wall and replace all the damaged panels up to the undamaged one. The last sheet is cut inside the nailer strip and the strip is removed. The sheet is then inserted as normal with the section normally attached to the nailer strip tucked into the last undamaged nailer strip still fixed to the wall. This may seem confusing, but I hope it helps. If you don't feel like taking it all down, just put some screws through it. Or, wait for the wind to blow it off and submit an insurance claim. It's a covered loss, I know.