Izuku had just fought a villan alongside a few other UA students. And him and a few others got quite badly hurt in the fight, whether it's a burn or few slashes on the arm

Izuku himself had about two deep gashes on his arm and a bit of blood on his cheek. But one of the people he knew had wounds too, so he ran over to them and started to bandage them up. He had a worried tone "Oh god! Are you alright?- do I need to get recovery girl?"