One hot & red cheek in 3month old

[Hobby2014]

Any ideas?
One cheek is very hot & red whilst the other is his normal skin colour and cold.
I googled and came across slapped cheek but it's not common in babies, usually children 6+.
Any ideas?
Thanks

Face cheeks, not bum cheeks.

My first thought was teething.

ds had it at 8 months , he was quite poorly, lethargic, hot, unhappy. Could he/she be teething ?

Sounds like teething to me, are the gums extra hard on that side?

Teething
Although you may not get any teeth for montgs yet, they are moving around in there.

Thank you. I knew their cheeks went red when teething but thought both would. I've just felt his gums and they don't feel harder. But is still early days I guess.

Sorry I didn't see the other post. Not lethargic or unhappy. Seems normal, other than being especially vocal today, but not crying, just chattering.