Additionally she drank too much water during her bath today and was regurgitating undigested food from yesterday. She's a little over 2 years old and her basking temp is between 100-105. Is this a pressing concern right now or just watch her going forward so it doesnt happen again? I baited her with a cricket to open her mouth to let it out and she's been acting fine since then.
It looks like a blood blister from an injury. I'd probably put some plain neosporin on it and keep a close eye out for any changes. Hopefully it will just heal over but if the damage starts working up the tail then I'd consult a vet.