Looks good to me. The idea of stretching it is fine although I don't know how well that would have worked. The thing with stretching is that you really need to have a way to control the stretch rather than being completely out of control as you are in the case of you body hanging down. If the stretch is too strong than you're muscles are going to try to resist it and that will just put strain on the injured area. Of course your muscle are always going to resist a stretch to some extent but the point it you have to be able to control it based on the level of discomfort. The key is gentle stretching with no pain in the case of injuries.
I know a lot of people like to do stuff "to get the blood flowing" with muscular injuries but the last time I checked blood supply isn't generally a problem in the muscles. If you have a joint injury it's a different story.
Don't let up your guard right now. When you pick up dumbells or whatever do it "correctly"
. In the future when you are healthy and you train well then some little dumbell isn't likely to hurt you no matter how you pick it up but right now always be aware.