Yes your fever blisters could go in and out of remission. You may have Herpes Simplex Type 11. Don't be alarmed. I just means that you are a carrier of of it. It has nothing to do with genital herpes and is not know to be carriewd to that area. Yes sun and stree can really aggratate it. the amino acid Lysine has been know to help (although it has been limited for me. There is a presscription cream called Denavir that has great results when you put it on just as you feel it starting. Good luck and i hope I have helped.