How Can Hyper Pigmentation At The Corner Of The Mouth Be Treated?

the corners of my mouth are cracked and dark on the sides of the mouth. Around lips are dry. I have a treated thyroid (hypo - medication taken is Levothyroxine 125mcg). In researching, I believe it to be Cheilitis. I also believe that the cause could be B2 and Iron deficiency. I have been plagued by constipation, my eating habits are not good ( i eat way too many carbs and processes snacks). My T2s & T4s are good however, my doctor said I am boarder-line diabetic. What would you recommend/prescribe that I do to about the symptoms of the cracked mouth corners, the scaling around the area where a goatee would grow?