A boy with severe epilepsy, who was admitted to hospital after his medical cannabis oil was confiscated, has been discharged.
Billy Caldwell, 12, was treated with the drug in hospital after the Home Office granted a 20-day licence for the use of the banned substance.
His mother says his seizures are reduced when he takes the oil and has called for it to be freely available.
The government is creating an expert panel to look into individual cases.
Home Office minister Nick Hurd told the House of Commons that the panel of clinicians, led by England's chief medical officer Dame Sally Davies, will advise ministers on any applications to prescribe the drug.
He said Billy's case had "highlighted the need for the government to explore the issue and our handling of these issues further".
But Billy's mother Charlotte Caldwell said there were still "unanswered questions".
Speaking to Radio 4 she said: "When will the panel be set up? When will it produce its report?
"This is something that has to be moved forward quickly and urgently."
Her comments followed earlier confusion when Health Secretary Jeremy Hunt suggested that Home Secretary Sajid Javid had launched a wider review of the law.
But Prime Minister Theresa May said government would look only at the current system of licences for use in individual cases.
"There's a very good reason why we've got a set of rules around cannabis and other drugs, because of the impact that they have on people's lives, and we must never forget that," she said.
Last week officials at Heathrow Airport confiscated Billy's cannabis oil, which Ms Caldwell had been attempting to bring into the UK from Canada.
It contains a substance called Tetrahydrocannabinol (THC), which is illegal in the UK but available elsewhere.
She said that Billy had been taken to hospital in a "life-threatening condition" on Friday evening, leading the Home Office to intervene.
During the weekend, Mr Javid granted a team at Chelsea and Westminster Hospital the 20-day licence to administer the medicine.
Ms Caldwell said: "The fact that Billy has been discharged is testimony to the effectiveness of the treatment and underlines how vital it is that every child and every single family affected in our country should have immediate access to the very same medication."
The mother, from County Tyrone, said she has rented a flat in order to facilitate this temporary treatment.
But she wants the law to be reformed, so Billy can have the medication administered at home.
"I will demand that the health department, not the Home Office, takes responsibility for providing access to medication for these incredibly sick children - this meeting must take place within 24 hours," Ms Caldwell said on Monday afternoon.
It is uncertain what will happen when Billy's 20-day licence expires, and whether the Home Office will continue to allow him to use the drug.
Cannabis 'got rid of tumour'
Raising an urgent question on the issue in the Commons, Gower MP Tonia Antoniazzi said there were two children - aged six and one - in her constituency who have a serious life-limiting condition and could "benefit hugely" from medicinal cannabis.
Other MPs also raised cases, including that of six-year-old Alfie Dingley, from Warwickshire, who also has epilepsy, whose family is awaiting a government decision on whether he can use cannabis oil medication.
Former Conservative leader Iain Duncan Smith - who said he is "by no means a supporter of recreational cannabis use" - shared the case of a woman who, after being given two weeks to live because of a brain tumour, used a form of the drug to get rid of the tumour.
Antoinette Sandbach, the MP for Eddisbury, told of a constituent's two-year-old son who has 300 seizures a day, which were reduced to about 50 a day following the use of cannabis oil.
Meanwhile, shadow home secretary Diane Abbott said the current system - even with the new expert panel announced - is "simply not fit for purpose" and called for the legalisation of cannabis oil for medical use.
Shadow transport secretary Andy McDonald, whose son died as a result of his epilepsy, also backed a change in the law, adding "I'm speaking out in the hope that further deaths can be avoided."
I’ve written to the Home Secretary urging him to allow legal prescriptions of cannabis oil for medical purposes.— Andy McDonald MP (@AndyMcDonaldMP) June 18, 2018
As a parent who lost a son to intractable epilepsy, I'm speaking out in the hope that further deaths can be avoided & families are spared the pain of losing a child. pic.twitter.com/KXee732n1W
Dr Julian Lewis, MP for New Forest East, likened the current issue to the relationship between the drug heroin and morphine, adding: "Why can't common sense prevail in the case of marijuana, as in that case too?"
Supporters of the Caldwell's cause also include the MP leading an all-party parliamentary group looking at medical cannabis, Sir Mike Penning.
He called the existing laws "bizarre and cruel", and added that "fundamental reform of the system" was needed.
"Medical cannabis is a health issue, not a misuse of drugs issue," Sir Mike said in a statement. "It's about patients and relieving suffering."
Does cannabis have medicinal benefits?
By Michelle Roberts, health editor
Cannabis contains different active ingredients and experts say some of them might be therapeutic for certain patients.
THC or tetrahydrocannabinol is the part that makes people feel "high", but CBD or cannabidiol is another component found in cannabis that scientists are interested in understanding more about as medical treatments.
CBD-based treatments have shown some promising results for reducing seizures in children with severe epilepsies.
Medical trials have largely focused on pharmacological preparations, but some parents of children with epilepsy have been buying oils containing CBD and THC.
There is currently little scientific evidence on the safety and effectiveness of these oils as a treatment for epilepsy, although they do contain the same active ingredients.
It is vital that you talk to your doctor or health professional before making any changes to your epilepsy medication.