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
Go to an emergency department now if you have sudden, severe pain in one testicle, especially with swelling, nausea, vomiting, or lower abdominal pain.
This may be testicular torsion, in which the cord supplying blood to the testicle twists.
Treatment is time-sensitive.
Emergency care is also appropriate if:
Severe pain follows an injury
A groin or scrotal bulge becomes very painful, firm, or cannot be pushed back
Pain is accompanied by vomiting or rapidly increasing swelling
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 for increasing pain or swelling with fever, redness, warmth, pain when urinating, or penile discharge.
These features may suggest infection and should not be managed with self-care alone.
Do not wait for it to become painful.
And for anyone, someone who:
is getting rapidly more short of breath, or has gained several pounds in a few days with swelling
3
Does any of this apply?
Book an appointment
Book a routine appointment soon for any painless lump, change in testicle shape or firmness, persistent swelling, or feeling of heaviness.
And for anyone, someone who:
has noticed a lump, a mole that has changed, or unexplained weight loss
Every sign above is quoted from the sofidex article on Testicle lumps and swellings. If you are not sure, err upward — it is always reasonable to be checked.