Karen Rand was watching the Boston Marathon with her friend Krystle Campbell near the finish line when two bombs exploded, killing her friend and seriously injuring Rand.

One of Rand’s legs was amputated below the knee, according to her son, Stephen Rand II. She is awaiting another surgery at Massachusetts General Hospital and has been recovering well.

Rand had sent out a picture earlier with Campbell, her son said, and when he heard about the explosions, he remembered how close she was to the course. He immediately traveled to Massachusetts from Maine.

“We didn’t know where she was,” Stephen Rand said. “We pretty much ran laps all over Boston.”

Rand’s family learned of her whereabouts only after discovering that authorities initially reported Campbell injured, rather than dead, because Rand had been carrying her identification and phone. It was 3 a.m. Tuesday before the Rand family learned of the mix-up, he said.

President Obama also paid a visit to Rand at her hospital bed.

“He came in and he said, ‘Hey, Karen, how’re you doing?’ ” her son said. “He was joking around, saying it was time for us to look after our mother.” Rand said Obama came at a time when the family really needed someone to lighten the mood.

Rand used a picture from the president’s visit on a donation Web site he created for his mother.

Despite losing a leg and her friend, Karen Rand has remained “true to the core” and “charismatic,” her son said. “She’s been really positive.”

He isn’t certain when his mother will be able to leave the hospital, but he’s confident about her recovery.