Car accident / legal junk -_-

Driving home from another province yesterday, I drive into a snowstorm. The road was covered in black ice, and I found that out by fishtailing, doing a 360 in the middle of the highway and ending up in the ditch. I managed NOT to hit anything or roll my truck, however I was perpendicular to oncoming traffic with my rear-end in the ditch and my front end was in the shoulder of the road. I was only going 80km/h.

A truck that was following me managed to clip the front-end of my truck with his door. He got a foot long scrape, while he managed to wreck my grille, 4 signal lights, 1 headlight, the bumper, and both of the panels around my front wheels. It's safe to say that I received the most damage.

In short, we both agreed not to call the cops and we simply exchanged information. I don't know if this was a good idea or not because I don't know who is really at fault: him or I. To my defense, I was on the shoulder of the road which means that he shouldn't be driving there. It was a good 10 seconds after I stopped that he managed to hit me. But am I at fault because I lost control of my vehicle?

Is it still too late to go to the police? What would the chances be for him to be found liable? Is there anything special I should do or know?

Jam it back in, in the dark.