If she's found wandering in an alley, she'll wind up in the ER or the equivalent. They'll deal with the cuts there. The confusion and incoherence would be enough to get her checked into the hospital for a couple days of observation, at least, especially since there would be no one to release her to
— hospitals are very wary of letting folks take off alone following a head injury. They usually want to be sure there's going to be someone at least checking in on her for a while.
If she hasn't started to make sense in a day or so, there would be serious concern about brain trauma — she could easily find herself under observation in a psych ward if MRIs/CAT scans show no sign of injury but she remains confused or incoherent. She also could wind up in a drug rehab ward, if the hallucinogen shows up in a blood test.
If any of the cuts did more than superficial damage to a large muscle, especially one of the ones necessary for walking or standing like the hamstring or quadriceps, they would want to keep her for a few days as well, to minimize her movement and decrease the chance of her re-damaging the muscle.
Who's going to pay for it depends on the politics and system of your world. In the US, the hospital must provide an established minimum level of care, regardless of her ability to pay. Beyond that level, they could bill her, or Medicaid, or the equivalent state department; they may have a disgressionary "charity fund" that they can pay for her care out of; or the hospital may simply eat the cost. If she's a particularly interesting case, or there's a doctor who is doing research on something that she could be a part of, that program might agree to cover her costs.
...if you don’t love you’re dead, and if you do, they’ll kill you for it.