For you to dislocate your knee, you have to fully tear some ligaments. They rarely happen except in car crashes, falls from buildings etc. Sounds more like it momentarily bent out of its usual range, which could be confused for a dislocation.
If you're having trouble walking on it and or it's swollen, get it checked out. If it was as gory as you say, you might have torn something that won't get better on its own. When I tore my ACL, LCL and posterolateral corner (v. bad injury), I just hobbled about for a week before going to A and E. It was a stupid thing to do cos I could have damaged it further and it just put me down on the waiting list for MRI and surgery.
Off the shelf knee braces offer very little support if you've damaged a ligament. It's like trying to fix your car with sellotape!
Hope it gets better soon!