Since it's over a week since you posted, I do hope that you did seek urgent medical attention and things are now improving.
What you described was that of an infection and will have needed a course of antibiotics.
Bacteria can enter through any breaks in the skin and infections can spread and become life threatening. Scrapes and wounds take longer to heal for people who have pre diabetes or diabetes.
Hope you are on the road to recovery.
Best wishes.
It is infected. You need to see a physician immediately who will decide whether debridement or drainage is necessary and prescribe an appropriate anribiotic. You can't let these infections get away. They can end up to be life threatening.