Just like last year, Sarah Girouard and a roommate from Northeastern University decided to spend the third Monday in April on Boylston Street, cheering on runners as they neared the Boston Marathon’s finish line. Then there was a blast and a burning sensation, and they were in adjoining hospital beds, both nursing shrapnel wounds.

For Girouard, a 20-year-old environmental science student, having someone she knew nearby in those early terrifying minutes was an incredible comfort, said her mother, Sue Girouard, who lives in Falmouth, Maine.

Doctors said a piece of metal, perhaps a BB gun pellet, pierced Sarah Girouard’s right leg near her knee, passing through the bone and exiting cleanly. More damaging was a thumb-size chunk of metal that lodged near her heel, requiring surgery.

No permanent damage is expected, her mother said, but Girouard will not be able to put weight on her right leg for some time.

“The heel is like an eggshell,” Sue Girouard said. “That’s the tricky part.”

“She’s a pretty tough cookie,” her mother added. “Fortunately, she didn’t see a lot of the horrific things that happened there. And it was comforting to her that she had someone with her that she knew, before we could get down there.”

Northeastern has offered to move Sarah Girouard to a more accessible, first-floor apartment when she returns, her mother said. It remains unclear when she will be able to return to her work as an intern at Boston City Hall. After three days in a Boston hospital, she is recuperating, surrounded by family, at her aunt’s home in South Carolina.

“Emotionally, she’s okay,” Sue Girouard said. “She’s a lot better than I am.”

“Sarah could be so much worse. We’re very grateful.”

— Joe Stephens