<human>: So, to start off, my mom is usually very helpful for me when it comes to watching my dog when I go away. She will usually do it without complaint unless she is unavailable and then I have to make other arrangements, but she doesn't charge me for it when she does watch my dog. I went away this past weekend and she said she would watch her no problem. 

On my way home yesterday when I was about 2 hours from home she called and told me that she had gone out for about an hour and when she came home my dog had eaten a 16.9oz bag of M&Ms that she had left in her work bag on the floor (she's a 24lbs dog so this is a large amount of chocolate), and she was going to call animal poison control ($69) and then update me on what's happening when she knew. She called me back a little while later telling me that she was going to get some peroxide because animal poison control told her that would make the dog vomit up the chocolate. She then called me again to say that my dog wouldn't take the peroxide and they were on the way to the animal hospital. 

I met her at the hospital where they had induced vomiting to get all the chocolate out. They then injected her with some fluids to help her system recover. My dog is fine now, but the vet bill was another $250. My mom seems to want me to pay her for it, but I feel that I shouldn't have to as she left my dog unattended with chocolate easily accessible to her. Am I in the wrong? Should we split the cost?

Give me the gist of the text in a nutshell
<bot>: My mom left chocolate where my dog could reach it and ended up having to pay >$300 for medical services. Should I have to pay her back?