I agree with Richard on the soaking. Use about 1/2 inch deep 80 deg water or thereabouts.

A friend of mine had a nice adult female with a similar condition. Can't say it was exact of course but in general she had a lump and lost weight rather quickly. The snake died shortly after. As I say, there is no way for me or you to know (at this moment) if your snake has this exact problem, so don't think I am saying your snake will die. I would hydrate as much as possible, provide a nice warm area and see a vet.
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Antaresia maculosa
Antaresia childreni

Mark G