Party ending up wrong.

Alright before i start i'm not posting this as my real user until i see i'm not trolled by idiots. A couple of days ago i was at a party with my gf and ran into jocks from my school. We were at a party and everyone was a bit tipsy, you know what i mean? I was lounging with my gf in the living room (as it was a house party) and the jocks came in. This is where it gets fuzzy, i don't remember much because this is near where i got knocked out. I wake up time later and the house is a huge mess and people have left. I get up and realise i feel fucked in my face, i touch it and I am bruised all over. I panick for my life frantically searching the house for my gf, waking up my friend who hosted the party. He says I got beat up by the jocks 'the usual'. I text my girlfriend and she says she's at her house and that I need to get there NOW. I arrive at my gf's house, she's crying. HARD. I ask her what's wrong and she says she got harrased. I was like by who? Chris. (fucking jock at our school.) At first i think this is a joke but then again, this links to my fucked up and bruised face. She explains to me what happened (Fucking shameful to state.) I cry myself and once this is over we tell the police. They are doing an 'investigation' but are taking time. In the mean while, everytime I go to sleep or have nothing else to think about, i think about revenge. I don't think murder is the right solution for this shit as he might probably get arrested, but everydat i'm fucking tempted to cut him open and leave him lying where people will see. I know this isn't the right solution but everyday the idea comes back, and bigger. Please help me on what I can do in the mean time. Thanks for reading this brick of text.