Sometimes, yes. When you drive, your car battery is kept recharged, either by an alternator on modern cars, or by a dynamo on earlier cars. So if it’s been flat and you’ve managed to jump start it, driving it will actually recharge the battery.
If you’ve been trying to start your car and it’s not working, waiting 20 minutes will let the reaction products diffuse away from the plates and the battery will crank away for a while longer, which might give the impression that it’s recharged itself.