I think Bianca might have a slight case of mouth rot. Over the past couple days, I've noticed that she's developed a sort of grayish scab on her lower jaw; also, she seems unable to close her mouth all the way (so much so that she's been getting bits of substrate stuck in her mouth). She doesn't seem to be in any pain, but I also don't want it to get any worse...is this something I can treat at home, or should I take her to the vet?

Any suggestions would be great.