dear user first these signs not indicative of having diabetes so dont worry of that but..........i would like to tell you that rashes of your arm and torso area may be due to some factors............if you had taken medication drugs rashes may occur from allergy of these medications or drugs........also if your skin contact with any corrosive material or allergen or had sting bite it may occur also............sometimes rashes follow fever or bacterial or viral infection as the immune system begin to clear that infection or micro organism and allergic reaction occurs that leads to appearance of rashes and i think this is important may led to these rashes........... it may also caused by varicella zoster infection or reactivation ( shingles ) if stress or sun exposure and that may need clinical investigations and treatment simply wish you healthy life