The symptom you are describing the most common condition coming to my mind is tinea, fungal infection commonly called as ring worm.this is seen when natural immunity is less.usually in your case the level of control of sugar is needed to know.for that blood sugar and HbA1C are required to be done.usually due to sub cutaneous injection skin gets thick and itching will not be there that too after long time use.any how physical examination is must to comfirm the diagnosis and suggest treatment. To control your sugar you need to focus on diet,no sugar,less oil,less salt,avoid fried foods,junk food. you can take watermelon,guava,papaya,black jamoon,one apple in one day,one masoombi. you should not take banana,grapes,chikoo,even jaggery. daily exercise like walking or gym is required to control sugar as well as body weight and also maintain adequate water intake.you should maintain personal and sorrounding hygiene to prevent these kind of fungal infections.