Anyone have idea what this may be?

My sister has a pain in her middle toe..it doesn't go away. Its as if she is stepping on a rock and sandpaper. She thinks it could possibly be from when her back cracked a couple weeks ago..it is perhaps a pinched nerve she thinks? Also she is diabetic and has had high sugars many years. Neuropathy? But that typically presents with off and on tingling. Any ideas?