Larsson and his son went to commiserate with the home crowd when a number of fans threw chairs and flags at them. A corner flag narrowly missed the ex-Parkhead favourite.
One of the pitch invaders appeared to strike the 19-year-old, provoking an angry response from father and son before stewards could intervene.
“I understand their frustration,” said Larsson. “That’s why I went over there. It was not the smartest thing for me to do.
“I live and work here in town. I will look over my shoulder a little more and make sure not to walk alone in town.
“If they (hooligans) come, they come. We have many dogs at home.”
The seven-time Swedish champions were relegated for the first time in 23 years, with Larsson having been in charge of the club he used to play for since the start of last season.