Prednisone can certainly raise blood sugars. While you are on this medication, you may find that your blood sugars are much higher than usual. You will need to give extra correction doses of insulin, and it may also help to eat low carb.
The high blood sugars causes by prednisone may take several days to weeks to return to normal. However, in some rare cases, the elevated blood sugars may persist quite a while.
If your doctor gives you prednisone he should tell you that you need to increase the insulin dosage, and eat a little lighter. Especially at night. My Doctor added Victoza to my regimen which helps lower my sugars. My prayers are with you as being diabetic and taking prednisone is no fun. Stress is another factor, it increases blood sugar as well. I like to do meditation for about 10 minutes a day. It helps. God bless you, things get better.