My bf doesn't know his own strength..

Marissa
Okay, so earlier today my boyfriend and I were together and stuff became a little heated and he began to move down to my boobs and began to tease my nipple. He doesn't know his own strength, and I'm his first serious relationship, and he took my nipple between his teeth then pulled away and ended tearing some skin..he's honestly an amazing guy and has never get me before, I know he didn't mean to. I said 'ow! Baby you gotta be gentle okay?' He kept saying that he was sorry and then just hugged me. I don't want to hurt his feelings or make him feel terrible, but should I tell him that he tore some skin? He doesn't know that he hurt me and he doesn't know his own strength. 
(Don't worry, it's not bad, it's like two little papercuts and he's never hurt me before; he's not like my ex (abusive)) 
So my question is: how do you tell your man that he hurt you and needs to be gentle without ruining his ego or what we have together?