The Scenario is UNLIKELY
As the query stands edited & clarified:
Your character should actually be in relatively good shape when her friends reach her! She will almost certainly survive, no RL, no magical herbs needed.
The wound you describe is entirely superficial. A slash across the abdomen that does not enter the peritoneal cavity has basically cut through skin & subcutaneous fat, with those layers' relatively small blood vessels.
It's a little unclear what you mean by a "deep cut" measuring "inches" that doesn't involve the internal organs. On a healthy and not terribly chubby girl, there's only about an inch of everything until you get right down to the wobbly bits inside. So I'm guessing the slash is inches long, which makes sense, because skin and muscle and even fat are not easy to slice through.
You didn't tag it, but your question begs for one. The reality is there just aren't enough major arteries or veins on the belly to cause a blood loss of two litres. That's an awful lot of blood and to lose that amount, you need some very serious arterial damage. A nick in the vena cava or one of the renal vessels will do it; but you say there's no internal organ damage, and the great vessels are too deep.
Short answer: the amount of blood loss you want doesn't jive with the injury you describe.
I suspect: that she passed out due to a vaso-vagal response. The sight of blood --- and to your character, a dagger slice will burn and seem like she's being gutted, and blood will be everywhere no doubt --- may be enough to make her faint. (The very thought of being stuck with a needle &/o losing blood is enough for many to faint!).
She landed on her back which is good. Keeps the wound clean. There's a 33% chance she'll land with her legs slightly elevated above her head, which will help conserve blood in her head.
Her friends arrive after a few minutes (say five) and find her to be a bloody mess. Those that don't faint or hurl their breakfasts immediately can do some basic shock and injury first aid to stabilise her wound and her overall condition.