Risk of Coldsore transmission under these circumstances?

I've suffered from coldsores from childhood (now in my 40's).  One thing I've noticed is that the typical "tingle" advance warning I used to get no longer happens (is this typical?)

The only warning I have is either:
a) A deep/painful and small "pimple" under the surface of the skin close to the border of the lip that - if left untreated - will develop into a coldsore
b) A reddening of at the border of the lip, a few mm in diameter that will develop into a coldsore if left untreated.  In all cases I use Abreva as soon as I notice one of these symptoms present, which turns things around or speeds healing.

Since the birth of my Son (now almost 3 years old), I've been very cautious about the risk of passing cold sores onto my child.  He loves to kiss his mum, and I try to ensure he only kisses me on the cheek... and I keep an eye open for the symptoms of an impending sore on my lips (2 or 3 times a year).

Today my wife and our son came into the bedroom to wake me up, and after he climbed on the bed he gave be a very brief peck on the outside of my upper lip.  Not having observed any symptoms I wasn't unduly worried, but was mortified when I discovered, shortly after, that I had a small area of redness developing under the skin at the border of my lip.  I suspect that this could be the first sign of a coldsore developing (our 2nd child was born 4 weeks ago, and things have fairly pretty stressful, with a lack of sleep... prime coldsore conditions).  

There's no sore, and are no blisters... this is likely the first stage of a coldsore "brewing".  He also kissed me on the dry part of my lip, but there's a chance it was right in the area the red area is developing, and he may have pecked me using the soft area of his lips around the area developing redness.

I'm very worried this may have passed the virus on to my son.  I would hate to pass something like this on.  Any thoughts on the likelihood of this having happened?

Thanks in Advance.

[Alan Rockoff, MD]

Given your description, I am doubtful that you passed anything on.  It does seem to me, though, that you are worrying far too much and possibly depriving your child of the affection he deserves and needs.  You might want to ask your doctor about taking an anti-herpes antibiotic like acyclovir every day for an indefinite period, so that you can be more confident that you won't develop an outbreak and spread it to your child.  Otherwise, you'll be staring at small and uninterpretable color changes on your lip.

Best.

Dr. Rockoff