So she went yesterday and basically we just chatted with the internal medicine vet and didn't have an endoscopy done. To summarize, it is the lower part of her small intestine that they noted on the ultrasound, and unfortunately that is an area the endoscope can't reach. It's possible that there are microscopic areas of inflammation higher up in her GI tract, that the ultrasound couldn't pick up, and if so they could biopsy those... but that's a gamble because there might not be inflammation higher up. SO an endoscopy might end up being a complete waste of time.
Of course, as dogs seem to normally do, she seems miraculously healed since this weekend, so this vet didn't think there was any urgency to do more diagnostics and she thinks we should just continue to monitor. Which I'm fine with now, but holy moly 3 days ago she looked miserable. But she was super wiggly and kissy at the clinic yesterday, and she hasn't acted that way towards people in a while! Also, today she shoved a toy in my lap for the first time in 3 weeks.
Ultimately I'm a little bummed because I just dumped a ton of money in this dog, and don't actually know any more than I did 3 weeks ago
But she seems to be on the up-swing so that's okay.