The image shared by u show that ur mother is developing cellulitis, is her blood
sugar under control it’s very important.
In diabetic patients even a small scratch can turn into cellulitis and Gangrene if blood sugar is not under control and patient mainland into diabetic ketoacidosis.
Ointment you are using is very good but we should supplement it with good antibiotic for safer recovery recovery
Next Steps
Feel free to consult with detail history for further guidance and prescription