Injection site 1 year old red ring

[Freezeboy]

1 year old had their injections in the thigh and has a red mark around one of the injection sites (they get given 4)

Put a mark round it at 9am and it’s still grown today by half a cm so now is about 4cm (which is a large amount considering they are only 1)

Really well in themselves, just had a longer nap than normal. Not off their food or drink.

I will keep monitoring but any suggestions on how to reduce this and at what point should I call the doctors (after 2-3 days after the injection and if it’s not getting smaller?)

I'd call on Monday, if I were you. It could be an infection. Hopefully not, but would you want to take a chance with a 1 year old?

Sorry, on second thoughts I think that if it were me I would ring 111 tomorrow morning. Growth of 1/2 centimetre in one day is a lot, and (as you say) especially for a very small child.