Kristine Donovan is a devoted mother who recently noticed a small, bluish-purple bruise on the back of her 5-year-old daughter Kailyn’s knee. Initially, Kristine thought it was just a normal bug bite, but it ended up being something far worse than that.

When Kristine first saw the bite, she figured Kailyn had gotten it in their backyard.

“She never felt it bite her,” Kristine said. “It could have been in her jeans, in the location where it bit her. We just don’t know.”

Kristine hesitantly allowed her daughter to go to school that day, but when she received a call hours later that Kailyn had a fever, she did not hesitate to rush her to the local pediatrician. As soon as the doctor saw the bite, he told them to take the little girl to the hospital immediately.

Within a day, the bite had worsened and turned black, and infectious disease specialists at UMass Memorial Hospital confirmed it had been caused by a black widow spider. The reason why the bite had turned black is that black widow venom kills the flesh around the bite.

Thankfully, doctors were able to treat Kailyn and the bite is healing well, but the little girl is still walking with a limp. Kristine and her husband Josh are going public with their story in the hopes of ensuring that nobody else will go through this. The want to urge other parents to “trust their gut” if they spot a bite or bruise on their kids and think that something is wrong.

Find out more in the video below.