Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
An erection lasting four hours or longer is an emergency, even if it is not very painful.
This is called priapism and can damage penile tissue without timely treatment.
Seek prompt medical advice if you develop a penile skin sore, bleeding, discharge, an unusual surface growth, or a groin lump.
These are not typical features of a simple fibrous plaque.
Get urgent medical care after an injury if you hear or feel a snap followed by immediate loss of the erection, marked swelling, bruising, or severe pain.
These signs can indicate a penile fracture, which is a tear in the erection covering.
Arrange a routine appointment if you notice a new firm area, penile curvature, narrowing, shortening, erection pain, or difficulty with penetration.
Assessment is also worthwhile if an established plaque starts changing or is causing distress.
Every sign above is quoted from the sofidex article on Fibrous plaques of the penis. If you are not sure, err upward — it is always reasonable to be checked.