Cold sore kisses..

So, I took my almost one year one (10 more days!) so visit his grandma, my mum today. She picked him up and kissed his face a few times, which I have always said was okay for her to do. But then I notice a cold sore on her lip, when I say something, she says she completely forgot she had one. Which is fine, she had just gotten home from work and I believe that she really did forget, my issue is just that she had already kissed all over his face (not his mouth, he had a sucky in his mouth) so, I guess my question is that is this still something to be extremely worried about? Should I do something about it? Is there anything I can even do? Make a doctor appointment? Or am I just over worrying?