Your are a Diabetic.
is a integral part of Diabetic management as a whole.
In long standing diabetes
due to peripheral neuropathy
the pain and temperature sensation of the foot is lost. It is a natural defence mechanism. So any trivial to the foot of the diabetics should be attained to.
that you have developed may be due to you walking in the sun on a bare foot or on an improper foot wear. Both should be avoided in the future.
Don't deroof the blister. Give a good antibiotic cover.
Consult a podiatrist.