question: Hello, I have a single red mark on my calf, about 3 inches below the knee. About the size of a small pencil eraser.   About 6 weeks ago I was clearing out leaves and thought it was an insect bite?  It took awhile to heal,  but recently rubbed/ irritated the scar tissue and it is now sort of itchy, stinging.  Nothing serious, but just thought it odd that it is taking so long to heal?  Can shingles present with just one singular blister? or is there usually a rash?  Thank you