Is this a cold sore?

[Thismombear]

My son last weekend had a fever and was sick and now this Friday I noticed this on his button lip. I don’t get cold sores and my husband doesn’t but I do know his grandma sometimes gets them.
He was with her 2 weeks ago but she has been good not to kiss or share drinks with him if she is having a break out. I’m still a bit worried.
He also has a rash on his bum but I figured that was because he was sick and just put some cream on him.
but I’ve never had one like I said a i’m not even sure what they really look like.

He is 4 years old and he didn’t touch his rash that I know of. And he always washes his hands after he goes to the bathroom. I’m not sure it looks to be on the bottom of his lip?

It’s difficult to say from this photo.
It will take a few days before you know for certain.

I get cold sores and so do my DC (because when they were young it wasn’t publicised about them being highly contagious) but none of us would go near the DGC without washing our hands first and all cups/glasses are kept out of reach, so none of the DGC get cold sores.