I want to approach this from a different angle, just as a thought experiment if you will.
You described touching the metal armor thusly "touching the metal armor made the druid feel uncomfortable, as if she was holding the slick carcass of a rotting fish." and then followed it with "it made her skin crawl, as if she were wearing something lifeless ungraved from the earth"
Your intent with this was to convey how the worked metal felt wrong and disgusting to the druid, correct?
So, in your world where mined and worked metal feels like a rotting carcass to a druid, then this would be accurate for a later scene.
"You walk into the dragon's hoard room and nearly vomit. The floor is littered with gold and silver that feel like rotting eyeballs slickly rolling around on the floor. The touch of it is like being in a charnal house, and your entire body shudders and rejects the sensation. You pick a magical scimitar, and it feels like you are holding a rotting limb."
After all, gold and silver are worked metal. If you had a shield made of gold, it would be a metal shield, so if it is the material itself that feels wrong... then druids would reject metal of all types. Coins, metal objects, bracelets, weapons they are proficient in, it'd make their spellcasting a little harder, spells like Reverse Gravity require them to have iron if they aren't using a focus, Not sure how to have a gem-encrusted bowl worth 1,000 gp if it isn't made of precious metals. Maybe it is made from some stone like jade...
Which is a point, isn't it. Some people say that the "no metal armor" rule is because of mining. Evil mining that destroys the environment, so druids reject metal armor.
So, why do they have no issue with gemstones? In fact, druidic magic requires gemstones, which have to be mined. Same with the Jade that makes the circlet for Shapechange.
So, do you keep consistent with your descriptions? Is the druid constantly assaulted every time they pick up a metal weapon, use gold to pay for anything, enter a fire giant's hall made of metal... or did you only include this description this one time to convince them not to wear metal armor, and that alone?