You seem to have developed a cellulitis
over your feet which is a bacterial infection.
that you have developed is also a part of the infection.
As far as rupturing of the blister is concerned, you need to do it very carefully. You should use a sterile needle for the same. Do not remove the roof of the blister. After rupture, let the skin settle down of its own and cover the raw area.
Apply a topical antibiotic
cream over the affected area after cleaning with an antiseptic liquid twice a day.
Keep foot end elevated.
Hope it helps
Dr Geetika Paul.