I've never had a cold sore that I recall. In November, I tried to do my own lip wax
(not worth the few quid I saved!) and ended up with a rash on my lip. It felt tingly and itchy and was a bit red and puffy but it was definitely directly related to the wax strips I used. Now I've got the tingling and itching again for several days but no cold sore has ever appeared. And no bumps or spots or blisters around my mouth, inside my lips, or on my nose.
I have had allergic reactions to toothpastes and skin creams before and recently used a new lip balm, but the tingling is just on one side on the top of my lip so it's got me to wondering whether this could be a cold sore? DH doesn't have any and I'm fairly certain neither of us is kissing anyone else. Loads of my colleagues have them and I'm wondering whether I might have picked one up from sharing the office telephone? 
xx