Callus Blisters are fluid-filled swellings in the skin. They may be a symptom of a wide variety of disorders, in which case they are usually accompanied by other symptoms. Blisters by themselves are commonly due to friction from poorly fitting footwear, or from a burn.
Regular or prolonged friction or pressure may also cause a patch of thickened skin, called a callus.
A blister caused by minor damage usually heals by itself. It should be left intact and may be protected with a dry, sterile dressing.
If a blister fills with pus or there is spreading redness around it, it may be infected and a doctor should be consulted. A serious burn also requires medical attention