She said she was taken to a nearby accident and emergency unit for a CT scan following the attack so her “head could be sewn back together”.
A 20-year-old man, who lived in the area, allegedly launched the assault after being refused an appointment at the hospital.
He was arrested at the scene on suspicion of wounding, affray and criminal damage.
Merseyside Police said he had been detained under the Mental Health Act, adding that officers would be carrying out high-visibility patrols in the area.
All those injured in the attack are now in a stable condition. They suffered head lacerations, injuries to their arms and hands and bruising.
Describing the attack on Facebook, Lynch said: “After a few blows to the head, I ran, I hid and did what I could do to get a door between me and him. I’ve been to Whiston A&E, who was absolutely amazing to me.
“My CT scans and X-ray have come back clear, and I’ve had my head sewn back together after cutting all the matted blood out.”
Police confirmed that a metal bar, believed to have been used in the attack, was undergoing forensic examination, and detectives were working through CCTV footage and witness accounts.
Sugedaran Shanmugaraja, who was working in the Best One shop across the road from the hospital, said an injured woman had fled the scene and come into his store.
He said the woman, whose head was bleeding, asked him to call the police.
“I gave her my phone to call. I could see blood and she said somebody was attacking everybody,” he added.
Hannah West, who lives across the road from the hospital, told the BBC she saw members of staff and injured people being evacuated.
She said: “I looked out my window when I heard constant sirens and saw some victims coming out and [a man] getting put in the riot van. Hospital staff were being evacuated.”
A Merseyside police spokesman said: “The 20-year-old suspect, who lives in Newton-le-Willows and is originally from Afghanistan, was arrested on suspicion of six counts of Section 18 wounding, affray and criminal damage.
“He was taken to a police station on Merseyside and has now been detained under Section 136 of the Mental Health Act.
“A scene remains in place at the community hospital while inquiries into the incident continue. A mobile police station is also on site, and people are encouraged to speak to officers with any worries or concerns.”
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