For an embouchure change - and the aftermath - I was given a very easy method by my last teacher. Heinz Troendle was Principal Trumpet with the Berlin Philharmonic under Karajan, and he suffered several motorbike accidents with facial injuries, forcing embouchure changes. He told me: Put all your upper lip into your mouthpiece, let the lips really relax, and produce the lowest pedal tone you can ever find down there. Hold that for a second or two. And then let the mouthpiece wander upwards towards a more normal position, until the tone slides into normal range." That will help you to center your embouchure within the mouthpiece - and a centered tone is a good sound.