Suggest Treatment For Pain In Leg After An Injury

My mum knocked her right foot into as chair 2mths ago. The knock resulted in blueness going over ankle area & halfway into the calf area. She's been to the GP as well as a Physician Spec. with results that there is no fracture, neither any vein blockage(scan done). She suffers with pain daily but there is no swelling in the area. She is 64yrs old & a diabetic and the GP is going to put her on the chronic insulin injection since her blood gluc. level is fluctuating up to 15(reading). Your response & assistance will gladly appreciated. Thnk you..