In answer to your inquiry to readers on lemon balm: Years ago I had an awful cold sore and found in the health food store a cream that had melissa extract which is lemon balm as main ingredient and was sold as a remedy for cold sores and it worked like magic!
I have tried a number of remedies for cold sores with no success: ice, apple cider vinegar, lysine (was ok), crystal salt deoderant (only helped the blister dry up). I get cold sores every couple of months so was very keen to find a good cure. I recently attended a medicinal herb workshop and was told to try lemon balm. I happen to grow it in my garden so I made a tea of it and have been drinking it 3 times per day. I found that within a day the cold sore I had went down and all pain subsided. It is now healing well. Additionally I have put some goldenseal ointment onto the healing sore and that is also clearing up a lot faster than normal. The teacher at the herb workshop said her husband use to get regular cold sores and he now drinks lemon balm tea often. He has not had a cold sore in years.
When Lysine quits working, which for me was at about 20 years, only Lemon Balm works.