
The black sticky blood is bleeding from the top part of the gut. Gut/stomach ulcers do heal, in humans and dogs, but other times there can be problems, depending how bad it is or on the cause. If they'd have been worried I'd have expected that they would have suggested keeping her in/ putting her on a drip/ doing blood tests. Have they put her on medication, and said when you are to take her back?
You haven't said if she is still vomiting? If she is, or passing a lot of blood I would ring and speak to them, out of surgery hours or not. Otherwise I would make a list of your questions about her so you remember to ask if you're due to go back - I'd guess they're seeing her again tomorrow? If she's OK in herself and they haven't asked to see her tomorrow then phone and ask them tomorrow - you're the one paying, and they're the ones that know exactly what's going on with her that can give you the most accurate answers.
But yes, I've known people with dogs with similar symptoms that have recovered and back to normal - but it doesn't mean they had the exact same thing wrong; it's hard to give an answer over the internet because of the different causes. And I have had an oesophageal ulcer - presumably healed, since it was 3 years ago, lol!!
Hope she's back to herself soon.