Rash help

[SparkleTea]

Hi, can anyone please help my anxiety is at an all time high. 10 month old is in a virtual ward for bronchiolitis with day 5 expected tomorrow.
Now my 6 year old has woken up with swelling on one side of his face and a rash extending on the one side down his neck.
He used to have sensitive skin which had gotten better as he's gotten older. Last night his auntie kissed him on the cheek the lipstick was near his eye where the swelling is, my husband washed it soon after. He says it's itchy and has been in the night but he never told is until this morning.
I've given him some antihistamines.
Do I see if that takes affect or do I brave 111 or a walk in centre?
Attached pictures it looks a lot worse in person.

I'd wait and see if the antihistamines had any effect. If it gets worse - particularly the swelling, then probably 111.

I would do the same as PP. I'd treat it as contact dermatitis with antihistamines and contact 111 if it got any worse. Has your son reacted to things like makeup or perfume before?
Just mentioning perfume because my DF used to get a rash like this if anyone he worked with used a particular brand of perfume. By the end of the day the rash would turn flaky. Amazing how fast the skin reacts