Dandruff is a scalp condition that causes the skin on the scalp to flake. It is not serious and contagious. However, it can be difficult to treat which may lead to hair fall and scalp infection and itchiness. It is is the dry white flakes of scalp, that you see on your hair, collar and on your t-shirts.
A cold sore is caused by HSV (Herpes Simplex Virus) as it generates various small and painful blisters on lips, mouth, nose, cheeks, etc. It is also known as fever blister. Cold sore is one of the common infection that 80-90% people get infected with any one form of Herpes virus. This infection can also be seen in children.