Baking soda and vinegar boom went of in my hand it started to bleed but the it started to swell get purple and get hard

Explosion: it sounds like you are suffering from a burn from the heat of the reaction and a contusion from the impact of the explosion when these two substances mixed. You probably have some broken blood vessels under the skin, resulting in purple swelling, and you should see a doctor as soon as possible for further evaluation to make sure there is no fracture or other damage.