the previous owner of my ES 350 apparently did not read the owner's manual and was not aware of the wiper winter mode and now as a result there are 2 spots each about 1 inch in length along the edge of the hood that are starting to rust.
how do i get this fixed without removing the hood?

 

Post a pic for best response. BUT, based on what you're describing, you should carefully sand away the rust and for best results use a chemical rust remover such as Iron-X and let it soak into the metal AFTER sanding the bulk off. The chemical will remove rust from any pitting in the metal where sand paper won't. Than you can use primer touch up paint followed by one layer of regular touch up paint and you should be golden.

If you really want to protect the area from ever rusting again or from further damage, you can even get a roll of PPF edge guard and lay down a strip on the back edge of the hood. This will prevent the wipers from hitting and damaging the edge of the hood in case someone by accident lifts them while washing the windshield etc. We typically wrap that edge when doing a full hood PPF install but an edge guard should do the trick as well and it's something cheap and easy to do yourself.

 

how can i sand the part on the inner side of the hood right by the windshield without removing the hood?

 

A fiberglass pen works well to remove rust in rock chips and the like. Using Iron-X is an excellent idea it does a great job of neutralizing rust. On the fiberglass pen use gloves the fibers are nasty if they get on your fingers. +1 to using edge guard on the hood, dumb design by Lexus my ES has the same flaw why didn't they put rubber protectors on the wipers. My old Camry has it to prevent this very thing.