My elderly corn snake keeps biting herself

[SammyLou]

hi y'all. I have an 18 or 19 year old lavender albino corn snake who I have found twice biting her own tail and refusing to let go to the point where I had to run her head under water. She will chomp town on her own tail and writhe and twist up. She also has taken to soaking in her water bowl quite a bit though she just shed last week. I thought her enclosure may be too warm but I have checked it many times and it's well within temp range on both ends. Has anyone else ever experienced this? I have read that snakes will bite themselves in their death throes but that makes me so sad! I don't want her to die, and also her appetite is totally normal so I'm stumped?? THANK YOU FOR ANY ADVICE