Baby With Chickenpox Kissed By Someone With Coldsore

[MYA2016]

I'm probably being massively PFB but my 11mo has chickenpox and my mum just said goodbye to him and forgot she had a coldsore! She pecked him on the lip/cheek.
She apologised straight away (I didn't even notice coldsore as it's in early days so just a red bump).
She said she felt terrible so I couldn't exactly be cross. But now I'm stressing. I'm guessing his immune system already will be low.
Should i do anything?

I'm not sure if there is anything you can do to prevent a cold sore from popping up. My mum has always had them and somehow my dad, me and my sis have never ever caught it. She also looks after my two DDs and they have never caught it, so it's maybe not that easy to catch anyway? Especially if the skin wasn't broken yet.
If he does get it keep an extra close eye on him in case it spreads through his already open skin. But I'm sure the chances are slim anyway. Hope he recovers from chicken pox quickly!