I just found this Hope it helps
it could also be scale rot
Blister Disease in Boas and Pythons
Boas and pythons will commonly develop blister disease, or vesicular dermatitis, if they are kept in too high humidity for their species, or if the cage substrate remains too damp.
In most cases, the initial vesicles are fluid-filled and do not contain any bacteria, however, in time, if the conditions are not corrected, any bacterial organisms found in or on the snake or its environment may contaminate the vesicles. Eventually, if left untreated, the bacteria can spread through the bloodstream, causing septicemia. In large herps, this process may take weeks or months, but with small lizards or snakes, death can occur in a matter of days. Mites can also spread bacteria to the vesicles.
Sometimes, the bacteria may form abscesses at the site of the blisters, and with the next shed, ulcers will occur once the purulent abscess material is gone.
Any snake with suspected blister disease should be immediately placed in a dry environment, with dry substrate and good ventilation, and correct ambient temperature and humidity. Since appropriate antibiotic therapy is critical to correct treatment, it is important that the snake be seen by a herp veterinarian ASAP for diagnosis, which may include a bacterial culture and sensitivity, biopsy or cytology, in order to choose the correct antibiotic for administration. A snake that is still eating and is active has a good chance of successful recovery. Please don't try to medicate a sick snake without the expertise of a qualified herp vet, as over-the-counter medications may not work and can cause a potentially life-threatening delay in seeking professional help.
