Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Call emergency services for:
Trouble breathing, facial or tongue swelling, faintness, or confusion
Extensive painful blistering or peeling with fever
A large or deep burn, an electrical burn, or a chemical burn
Blistering after smoke inhalation or with breathing difficulty
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek same-day medical care if bullae are spreading quickly, very painful, or accompanied by fever, increasing warmth, swelling, pus, red streaks, or worsening tenderness.
These can be signs of infection or significant inflammation.
You also need urgent assessment for blisters involving the eyes, mouth, or genitals, especially if several areas are affected.
Get urgent help if widespread blistering or skin peeling begins after starting a medicine.
Bring a list of prescription medicines, over-the-counter products, and supplements.
Seek advice promptly for a foot blister if you have diabetes, poor circulation, reduced sensation, or a weakened immune system.
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if bullae keep returning, have no clear cause, heal slowly, or leave repeated sores.
Every sign above is quoted from the sofidex article on Bullae. If you are not sure, err upward — it is always reasonable to be checked.