I'm not sure this is the thread for this, but I have added recent photos.
I'd definitely stay away from a newborn with a cold sore. DS1 probably got his eczema herpeticum from my Mum - she had a cold sore at the time and we were staying with her. I've never told her though. Next to us she loves him more than anyone else in the world. How would she feel if she thought she factored in his regression.
I understand why the mother is feeling guilty, but she shouldn't. It could have come from anywhere. The issue is better training for medical staff to consider/recognise herpes infections. Acyclovir is an effective (although expensive) drug - the issue if recognition.