I wouldn't lance any blisters without her being on antibiotics. Still probably not a good idea. Snakes that have been chronically starved can end up with permanent
skin damage (or very slow to improve), sometimes with fluid under the skin. Vet visit to very experienced herp-vet would be your best bet. Might also ask about
supplementation with Vit C...that has been discussed here in a couple past threads with similarly rescued snakes. For the moment, just work on building up her
health with decent food.