I screwed up!

Some LED bulbs won't work with polarity reversed, but a regular incandescent should still light.

Never saw a fuse box with a red light, doesn't mean there aren't any. Sometimes you can see one fuse has a broken filament. Best way to check is with a test light.

A short should not have any effect on the bulbs, just pop the fuse in the circuit. That's what fuses are for and there should not be any other damage.

Reversed polarity on a 12 v dc system should only cause the fan to run reverse of the switch indication in an isolated condition. I suspect that grounding by reverse polarity popped your fuse. Shouldn't be any other harm.
Test your wiring for correct polarity.

All reversing the polarity would do is make the DC fan motor run backwards. Unless you shorted the wires and blew a fuse, it's more likely that you might have a bad connection that's interrupting either the ground or hot wire to the lights. Were there more than two wires at the fan power connections?

Quick question -- does the red light come on if the fuse is removed? Or just blown?

Yep - didn't see any red lights lit though. Will check again when I cool off.

Have you checked your 12v fuse panel?A blown fuse should show an illuminated red led light next to it (on mine anyway)