Regurgitation help?

[Bogertophis]

I believe she's 139 grams.
I was under the impression that u waited 1 week then u could handle, now I know I should wait a few weeks providing the meals are consecutive. Unfortunately no thermostat, I'm currently looking into it, not sure which brand is good / right for a decent price. I heard to not trust jumpstart. I don't know how old she is as the store I picked her up from gave me zero info (I was surprised I didn't get any papers attached to the cardboard carrier they put her in). I don't know how much the mice weigh as I didn't weigh them. She was a bit thin (could feel spine but no ribs and no bumps or anything) and had a bit of triangular type shape.
I am using frozen / thawed mice from petsmart. I thaw them in the fridge and then put them in a ziplock bag and put them in water as hot as my tap can get. I wait for awhile and feel them to see if they are warm before I feed.

It's really critical that you regulate the heat...BPs need a warm area that's 88-90*, but over that & they can get thermal burns, which will kill them faster than starvation...not to mention their pain & suffering. They crave the warmth but don't seem to have a good sense about what is "too hot"...maybe because they have thicker bodies? But you must regulate the heat, and be able to measure it accurately. Sounds like your local pet store wasn't much help either. Without seeing her, hard to say how serious her weight issue (being thin) actually is, & she may also have regurged at the store...not all stores are forthcoming about issues, they just (sadly) want to make a sale. After a snake has regurgitated, it's important to feed them smaller items...fuzzies would be more digestible for her (less fur & small size). To make sure she takes f/t, many here also warm them with a blow-dryer briefly, right before offering, to bring their temperature up to "life-like", & of course use feeding tongs. I'd highly recommend using a pinch of reptile "pro-biotics" on her food too (as I think was already suggested), to help her digestion, once she's ready to feed again. You can likely help her thru this but you do need to get things dialed in & stay vigilant.