my 13 yr old accidentally hit the baby in the forehead tonight, Im not sure how hard. The baby was…

my 13 yr old accidentally hit the baby in the forehead tonight, Im not sure how hard. The baby was laying on my bed right against my leg while I was on the phone, and my son jumps up on the bed. As he's adjusting his position on the bed, his knuckles hit the baby. He cried for a minute and I picked him up and held him and he's seemed fine all night. No bruises or marks or swelling. But he didn't want to fall asleep till just now which is unusual for him as he goes to bed at 8:30 every night. He was also extra fussy for the last hour. Should I be worried? Do you think I should go have him checked?