Could fever blisters be the cause of a allergic reaction to Lactaid milk?

Fever blisters are caused by the herpes simplex virus, not by an allergic reaction to Lactaid milk.

Lactaid milk is milk that has had the lactose removed. Lactose is a sugar found in milk and other dairy products. Some people are allergic to lactose, and they can experience symptoms such as bloating, gas, and diarrhea. However, fever blisters are not a symptom of lactose intolerance.