Don't use tea tree oil or alcohol. Tea tree oil in the essential oil form is a natural anti fungal. Cold sores are caused by the herpes VIRUS. The tea tree will burn her skin, and if she ingests it, can be very harmful. The alcohol isn't good for her skin either, and won't do anything but make her skin dry and crusty.
Keep the area clean and dry and make sure that she is taking a good quality multi vitamin. (We use Natrol liquid multi vitamin for our 3 year olds). L Lysine is an amino acid that can help shorten the outbreak, or even prevent it if used daily. I would get her an ointment form and put it on according to the directions. I would avoid taking it orally at her age.
You can find L Lysine at most health food stores, but GNC has one of the best selections, along with a good multi.
at 11:36 AM on Feb. 7, 2010