Thanks for posting your query.
Your father 's illness is all because of suppurative lesion.
Suppurative lesion means infected pus collection which is very common in a diabetic patients.
Uncontrolled sugar and associated peripheral artery disease
promotes pus collection.
As he is already taking antibiotics and on improvement side, he should continue the same and if size is not decreasing then he must consult with general surgeon
for incision and drainage
ESR is a non specific test which indicates some disease activity is going on in body.
He should also consult with internal medicine specialist / endocrinologist
and should go for thorough check up.
His blood sugar and glycosylated hemoglobin
must be in controlled range.
Dr. Mayank Bhargava