Dislocated kneecap due to soccer stretch?

Today i was strbefore football and i dislocated my kneecap my first instinct was to grab it and put it in place but i also went to hospital with it, i have been given a course of co-codomol and have been told to report to the fracture clinic just now, although not sore to walk on it is very very uncomfortable as it feel it will slip out again.........what is the usual recovery for this and will i be on crutches for long ??