Evil Doctor and Poisonous Lady

I traveled back in time to a little girl who was not well-liked by my second concubine and was bullied everywhere. Even though she didn't know martial arts, she actually had to be a dowry girl. Is this wrong? Okay, if I can't beat you, I'll run away! Why is even running away from marriage so thrilling? I finally survived the catastrophe, but because I accidentally stepped on a broken grass, I was forced by this man to learn medicine and poison, otherwise I would be a slave for life. God, what kind of world is this! Since God wants to keep me, wouldn't it be unfair if I don't apply what I've learned and turn the world upside down? But when did this man change his claim to be a teacher to a husband? Who will give her an explanation?