Port wine stains (or nevus flammeus as they are known medical) are a type of malformation of the blood vessels that are usually congenital (you are born with them) and that cause dark purple stains on the face and elsewhere. I am glad to hear that you are pursuing treatment for this, as port wine stains, unlike other types of birthmarks, do not tend to fade over time.
Laser treatment is the method of choice for help port wine stains to fade. This laser treatment, although generally safe and well tolerated, can cause bruising, pain, and inflammation of the treated skin.
In order to minimize your discomfort and anxiety
during and after the procedure, you will want to talk to the dermatologist
who will be performing the procedure to determine what your anesthesia options are. Different dermatologists have different preferences on which types of anesthesia to use, ranging from topical agents to oral pills and even, in cases where the procedure is anticipated to take a long time, general anesthesia in an operating room. You should discuss your concerns with your dermatologist and, together, you will be able to decide which anesthesia option is the best for your particular case.