I'm and off opiates now and recently I had itchy red bumps on my foot they itch for a while and become a blister after. The blisters get huge and it doesn't go away until I pop it and ripe the skin off. It just fills up if I don't ripe the skin off. My sis

Dermatitis. Vesicular tinea pedis which is a fungal infection can cause blistering and itching. There is also the possibility of a contact dermatitis which is a skin allergy, albeit less likely since draining and drying of the blisters seem to relieve your symptoms.
Try an . Antifungal cream. If doesn't work, see a doctor.