Mouth & Lip Sore

Last night my nephew was over, he is younger and he was playing with my cat...a little rough. I put the cat in the other room, at which time she appeared fine (just annoyed!). However, I woke up this morning and she has a sore on the outside of her mouth, and a bruised lip. I am guessing her lip became bruised when he was "playing" with her, and am not worried much about that as it will heal. What I am concerned about is this mark on her mouth. I have linked pictures. Any clue what this is? Part of the bruise? Will it heal and disappear?
   
http://i69.photobucket.com/albums/i75/TheHulkOwns/100_1294.jpg
   
http://i69.photobucket.com/albums/i75/TheHulkOwns/100_1302.jpg
   
http://i69.photobucket.com/albums/i75/TheHulkOwns/100_1305.jpg
   
http://i69.photobucket.com/albums/i75/TheHulkOwns/100_1305.jpg

Also, she is eating, playing, and acting normally. She just flinches if I touch the area of soreness (to take pictures).

This doesn't look too severe and I would expect it to heal normally. Make sure that it forms a nice clean dry scab and that the cat doesn't continually lick it or re-open the wound. If he's behaving normally otherwise he should be fine. It may leave a faint scar but the cleaner the wound and faster it heals the better.