My cat Sammi Sam has a gash in his cheek ive treated it now what do i do?

My outdoor adult male cat came home a few days ago with his left cheek fur pressed down, I figured he had just rubbed up against something sticky and it pressed his fur down (wouldn't be the first time). 2 days ago we noticed a horrible smell and traced it to his cheek, after further searching we found a gash so we cleaned it out. TOnight when we cleaned it out a lot of gooey white stuff came out of it, we got as much out of it as we could and put some neosporin. It's large enough to fit a q-tip into ( i didn't put one into it just an estimate.) He's not acting like it hurts, still running around jumping and loving his eating hasn't changed or anything. I'm just worried.... is there something more I should be doing? Please help.