Oral shingles, like other forms of shingles, occur on only one side of the body. They cause blisters that ulcerate. These blisters generally start as tiny, fluid filled blisters. They generally occur on the lips or in the mucous membranes inside the mouth. The blisters may begin with itching,or sensitive areas of skin around the mouth. An oral outbreak could be one blister, or a cluster of blisters. The blisters are usually painful, and they ulcerate and then crust over. These lesions generally heal on their own in 7-12 days, but there are over-the-counter as well as prescription remidies to help lessen the symptoms.