SD card damaged?

[Axel Foley]

Yesterday, my phone froze and I took the battery out and put it back in, then restarted it. The phone has worked fine ever since, but now whenever I turn it on I get a notification saying "Damaged SD card" with the subheading "SD card damaged. You may have to reformat it." This notification doesn't go away.

So I'm trying to figure out--might I actually have damaged the SD card? Because so far, I haven't noticed anything amiss. And also, how do I get this notification to disappear? Thanks for any help.