I'm having a dime size basal cell carcinoma removed from between my nose and lip. how large should the scar be?

Small: The size of the lesion is medium sized. Mohs microsurgery can offer best control and there will be a scar associated with it probably not very big. Radiation has slightly less chance of cure but does not involve cutting so less scar and at times it is favored because of favorable cosmetic result it provides for the location you discribed. Talk to your doctor.

Unknown: Depending upon the true extent of the cancer, the technique used , and the available tissue for closure. Obviously this can't be aswered in this forum. Talk to your surgeon.

Not predictable: Not possible to predict just from the superficial appearance of the lesion. It may just be the "tip of the iceberg". The lesion may be much larger than it appears at the surface which is why mohs is the most precise method to remove the cancer. It eliminates the guess work by allowing the surgeon to see microscopically how far the cancer has invaded and ensures the smallest scar possible.