"In four days' time, we went from thinking everything is going to be OK and we'll put her in drug rehabilitation to now you don't know if she's going to make it," he said.

The doctors at North Cypress Medical Center told the family there was nothing more they could do. She was sent to Children's Memorial Hermann Hospital. Citing patient privacy, doctors at Children's Memorial declined to be interviewed.

No consistency, no way of knowing

Knowing how different people will react to fake weed is impossible. There are a few reasons that explain why.

"You're hearing some pretty bad things with the synthetic cannabinoids -- part of that has to do with the potency. It can be 100 times more potent than marijuana," said U.S. Drug Enforcement Administration spokeswoman Barbara Carreno.

"Anything that was truly a fake pot wouldn't be making your heart race. I've heard of palpitations with marijuana, but not tachycardia."

Carreno explained there's no consistency or quality control from one time to the next. The people making these products can be anyone from a college kid wanting to make extra cash to an operation blending large quantities in a cement mixer, she said. Two batches made by the same person could have different doses.

CNN showed Carreno a picture of the packets of potpourri Emily reportedly used -- the teen's friends gave her family the pouches after the incident. One black wrapper adorned with marijuana leaves reads "KLIMAX potpourri" and both labels read "KUSH TM."

"It's definitely a synthetic cannabinoid," Carreno said after seeing the photo.

The potpourri displays at stores also include a label that reads "not for human consumption."

Carreno called these labels a "cynical attempt" for the distributor to dodge the Controlled Substances Analogue Act, which covers any chemical similar to controlled substances such as cocaine or marijuana. It states that substances mimicking an existing illegal substance, such as marijuana, are also illegal.

"Everything about this is a lie," she said. "They're not potpourri. They're called that as a smoke screen for people naive to drugs and not to admit that it's drugs. But you can see it that they are."

From joy to nightmare

Up until Dec. 13, Emily had been in an induced coma the whole time, said her stepdad. Her only movements were involuntary reflexes.

"Seeing her in the hospital, she was literally just a shell. There was nothing in her eyes. She was just lying there alive minimally," said Harrison.

ICU doctors said some of Emily's blood vessels were starting to open up. Harrison said it was a glimmer of good news that was quickly snatched away: "We all grew overjoyed, little did we know this would become our next nightmare," she wrote on CNN iReport.

The pressure on Emily's brain skyrocketed, she said. Doctors asked to drill a hole in Emily's skull and insert a tube to relieve pressure and drain excess fluid. The family signed off on an emergency surgery.

"The family waited and cried, we had no idea if we would ever see Emily again, but we knew that even if we did, we will never have our old Emily back," Harrison wrote on Dec. 14.

It was a tense hour, but Emily pulled through.

What would Emily want?