I’m very sorry to hear that. While I am a (hopefully not permanently) retired veterinarian, I am not too proud to acknowledge that I am rusty and not an exotics vet. An entomologist should be able to guide you in the right direction re:type of parasite, then you can share that info with your vet, and that can inform treatment. There is sometimes an issue in mammals with treating patients that have a heavy parasite burden, whereby the sudden death of all the parasites causes a chain reaction that can make treatment difficult. However, I have seen animals in those situations pull through, when one goes in anticipating it. I’m not trying to argue either way, just offering what I know that might help.
Whatever you do, do not forcefully massage. I have seen snakes pass away after exactly this, even in an (exotics) veterinary situation. In the case that comes to mind, the lump was related to a food item becoming impacted in the GI tract, with lower temps a suspect for the cause of the inadequate passage of the prey. Perhaps that happened, causing damage to the GI tract, and the infestation is secondary to that somehow? Not what I would expect, just throwing out some ideas.
Should you decide to cull, there was a recent thread discussing the culling of snakes.
Thank you again for sharing her story.