Any discoloration to it? Has it gotten better or worse? A photo would be nice, if possible.
Have you inspected it's body thoroughly for other blisters? Are the belly scales a normal color?
Yes, it's possible it's from a rodent bite, if you've fed it live prey. That's a bad area to have a bite or lession due to the high possibility of it getting contaminated with urine and feces. There are other possible causes but need more info.
Best wishes!
HH
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Due to political correctness run amuck,
this ol' hillbilly is now referred to as an:
Appalachian American
