MicroSD card won't read anymore and SD card slot got really hot

I've been using the MicroSD in my Yun with no problems since I received it last December. Today I was using the server/client combo as usual with no issues until I would get "Warning: Problem accessing board folder /www/sd
" in the IDE error window. Confused, because I've never had this error before, I went over to the Yun to inspect the SD card, and when I touched the card holder it nearly burned me. Now I can't reformat the card, I'm guessing it has been corrupted.

I will say that I had my Yun on for a while, probably an hour or two, but I still don't see why I had this issue. Curious if anyone has any thoughts on this...