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 if you develop trouble breathing, swelling of the tongue or throat, fainting, severe confusion, a seizure, or rapidly increasing weakness.
These may be signs of a serious allergic, neurological, or infectious problem.
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 urgent medical advice if you develop:
An expanding rash after possible tick exposure
Fever, severe headache, marked tiredness, or widespread aches
Facial drooping, numbness, weakness, or difficulty walking
Chest pain, a racing or unusually slow heartbeat, or faintness
A spotted or purple rash, especially with fever
Spreading redness, worsening pain, or pus at the bite
Contact a healthcare service promptly after a newly removed tick if you are in an area where Lyme disease is common and think the tick was attached for a long time.
Preventive treatment, when appropriate, has a limited time window.
And for anyone, someone who:
has a wound that is hot, spreading red, or leaking pus
3
Does any of this apply?
Book an appointment
Routine advice is reasonable if you cannot remove the tick, cannot identify what is attached, or are concerned about the bite.
A small stable bump without other symptoms can usually be monitored at home.
The article also says
Tell the healthcare professional when and where the possible bite occurred, including recent travel.
Every sign above is quoted from the sofidex article on Tick bite. If you are not sure, err upward — it is always reasonable to be checked.