Oh gee yes, see your Doctor. A serious complication in the feet from having diabetes can be Nueropathy. Wounds, cuts and ulcers can be a serious matter under circumstances. But it could be (hmmm...) Gout? Gout is a build up of Ureic acid which cause these crystal "things" (lol) to develop into sharp edges which can dig into the tissue. Gout usually causes inflammation around the joints especially in the toe area (particularly in the big toe) but can occur else where. Redness & inflammation are an indicator. That being said lol, it could be just about anything! lol Maybe even just a tootsie boo boo. I hope it feels better soon and if it gets worse at anytime, see your doctor right away.