How to tell someone their a bad kisser?

My boyfriend and i were making out the other night and it was very bad. The tougne and everything was great but his teeth were digging into my top right part of my lip! i woke up with the fattest lip of my life.. it was all black and blue and now scabbed over. soo noticeable and painfull!! is there any tips or suggestions how to change how i make out so he doesnt do this? or any way thjat i can tell him with out actually saying, oh hey your teeth are digging into me? haha help pleaseeeee!!!!!!!!!!!!!