My father who is 75 years old has been getting sores on his arm. it is almost like a purplish/maroonish bruise that appears only on his right hand every few days. please can you tell me what this could be? he is a diabetic and has hypertension?

Bruising ?'s: Vascular fragility is common at 75, and even unnoticed injuries can cause rupture of small veins on a dominant hand. Since this is a repeating phenomenon, if your father takes anticoagulant therapy, minor bruising may indicate his INR is too high. See a hematologist for a clinical opinion.

Hand bruises: I suspect that these are not sores but blood leaking from tiny blood vessels on the back of the hand (not the palm)where the skin is very thin and fragile in elderly people. The bleeding(ecchymosis) can be spontaneous or from minor trauma and will be more common if the patient takes blood thinners,aspirin, ibuprofen, naproxen. This is not serious bleeding as opposed to nose bleeds or gum bleeding