How would people react if they found out i cut myself?

hi...i'm 13 and in the eight grade and i have been cutting myself these past few months...but i only cut on my left arm and the cuts are a little close to my wrist...i were a jacket everyday but you can still see the cuts close to my wrist...(i'm a guy btw)...and i want to know what the reaction would be if one of my class mates saw the cuts....and i know that guys can be a lot different from girls in this situation... so it would help if i got an answer explaining the reactions of both.... i have bipolar disorder btw...