I'd put my money on a separated shoulder. The way he fell at that angle puts a lot of pressure on the AC joint which is where your collarbone and scapula (shoulder blade) meet at the top of your shoulder right before the meaty part.
It's painful and there are different grades of severity, but I played with and coached numerous kids who had separated shoulders, I think only 1 required surgery after the season was out. Otherwise you could play with it that day, a week later, or 2-4 weeks later with rehab. Also there are equipment adjustments that can be made to help, spider pads and a ring pad can be put right over the "knob" and under the shoulder pads.
If that's what it is, CJ is in a lot of pain right now, but I'd take a separated shoulder over a dislocated or subluxed shoulder any day. JMHO after two shoulder surgeries in college for dislocated and subluxed shoulders.