That is the sad part of ensuring quality product is given to the end user. You can approach consumer protection bureau for your rights on this. Suggest you take it to the 3S dealer you got the car from and give him a piece of your mind.
For future, make sure no one over spills the battery acid. To avoid corrosion on the terminals, drop a few drops of brake oil over the terminals and connectors. 1-2 drops max, just enough to cover the battery terminal. Should not drip on the body or metal.
The acid spill eats away the paint and leave the metal bare, prone to rust. If left uncatered, it could weaken the area.
If the dealer or Honda dont do anything about your problem,
then here's what you do.
*) Clean the affected area + the surrounding with sand paper till there is no sign of rust. The clean metal surface should show.
*) Get a harder primar and coat the surface, if you want you can coat it with red oxide. Let to dry for a day.
*) Finish the surface with # 1500 wet sand paper till the surface as smooth as baby's buttocks
*) Either apply matching vehicle paint or black paint over the area.
*) Apply a thn film of grease over the area where the spillage occured to avoid any further mishaps. You can also spray some WD40.
BTW, The 3S dealer would do the same thing & return it to you saying they did God knows what.