Detention what should i do ?

Well i got a detention for saying almost nothing when the teacher left the roon but other people were talking for the whole lesson and i didt he got cross with them but when he came in again he heard me talk and gave me 1 hour alfter school well im going but dnt wont my parents to no and theres football trial that day alfter school i was thinking of saying to my parents im going to football but instead i go to detection wot u think