3 miles into my ride this morning and I pinched my rear tire on a turn. Still trying to learn to be proficient at changing/repairing a flat in the field. I'm equipped with a patch kit and CO2 cartridges. I bought one of those Topeaka CO2 Cobra triggers. It worked fine and I was able to ride home the 3 miles for a total of 6 miles.

My questions are: Does the tube need to be drained of CO2 and filled with air? And should the repaired tube be discarded in favor of a new one?