Teeth whitening home remedy backfired, help please?!?

i read about using hydrogen peroxide & baking soda together to whiten my teeth so i decided to try it. i started brushing my teeth with it and felt an extreme stinging sensation. so i gargled it out with peroxide like the next step was, and the bottle burst. so then i gargle it out with water. my gums have white spots that hurt really bad and were bleeding. whats wrong and what can i do to start healing ?