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
Seek emergency care after an injury if there is a popping or cracking sensation, sudden severe pain, immediate loss of the erection, rapid swelling, or dark bruising.
These may indicate a penile fracture, which is a tear in the covering of the erectile tissue.
An erection lasting four hours or longer is another emergency, whether or not it is painful.
This is called priapism and can damage erectile tissue if treatment is delayed.
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
Blood at the urine opening or difficulty passing urine also needs urgent assessment.
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if you notice:
A new curve or one that is becoming more pronounced
Painful erections
A firm plaque, narrowing, or loss of length
Difficulty with penetration or maintaining an erection
Distress about the appearance or effect on intimacy
The article also says
Curvature by itself is not usually an emergency.
Every sign above is quoted from the sofidex article on Curvature of the penis. If you are not sure, err upward — it is always reasonable to be checked.