Panacea doesn't take requests, and also doesn't do brains - and while Lisa's brain is nominally intact, as she is would be cutting it pretty close.
But that's mostly excuses; the bigger issue is that Taylor really isn't good at accepting failures and asking for help, and also, well.
Tattletale's a crook, Taylor knows it, and Taylor's not the most trusting individual at the best of times. She's not going to take the chance that someone else might decide that it'd be better if Tattletale died.
By not taking requests, Amy means she wont do cosmetic surgery - ie bigger boobs, nose jobs. This is certainly
not that, in the same way that removing an inoperable tumor is not cosmetic surgery. She wouldn't ignore somebody bleeding out in front of her because the hospital staff didn't organize the meeting, so theres no reason to assume she wouldn't save Lisa if Taylor brought her in.
As for the no brains thing, this doesn't break her rules. Lisa's brain is almost 100% intact, or else Taylor would probably have given up. Amy would be making a body for the brain to fit into, the same way she would be basically remaking the body of a cancer patient. She doesn't refuse to heal people with stage 4 cancer, there's no reason to assume she wouldn't give Lisa a body.
As for Lisa being a crook, Amy has no idea what Tattletale looks like or what her DNA looks like. There would be no connection made there. Taylor could simply say 'I found her near death and the only thing I could save was her brain
HELP!' and she would practically fall over herself trying to do so.
The real problem is that making a new body for Lisa would reveal just how powerful she really is - after all, healing is much different from making an entire body out of meat. Which means that either her true power would get out, or she would be forced to let Lisa die.