"I just want her to come home, or at least call someone so we know she's safe," Cummisky said. "We just need to know. We're all sick."
Geer, who has lived with her father and stepmother in Malden since 2011, went missing for 24 hours about 10 days ago and returned home, but had not previously run away, said Cummisky, who lives in Marlborough. She didn't know why it happened.
"There wasn't any one big thing, like a fight or anything like that," Cummisky said.
While she hasn't been in touch with her family, Geer contacted her ex-boyfriend Sunday to say she was OK, but did not say where she was, Cummisky said.
She is believed to be with another girl who has previously run away, said Cummisky, who described her daughter as outgoing.
Geer's family has received an outpouring of support after a friend of Cummisky's posted a copy of a missing person flyer on Facebook. It had been shared nearly 27,000 times as of Tuesday evening.
"I've been overwhelmed," Cummisky said. "I can't thank them enough, I didn't think that social media would extend like this, I have no words for it."
Cummisky said they received tips that Geer was in Revere and Everett in recent days. She is about 5 foot 3 inches with light brown eyes, long black hair, and weighs about 110 pounds. She is likely wearing a black wool coat and has a nose ring, Cummisky said.
Anyone with information can contact Cummisky at 508-933-4776 or Malden Police at 781-322-1212.