Signed As Guarantor For Grandmother In Emergency Er. Will I Be Responsible For Her Medical Bill? Texas

My grandmother is a temporary visitor. She fell by accident and was sent to ER because of fracture. She has dementia so I signed for all the paperwork in ER. I did not know at that time that I am signing as a guarantor (had no previous experience like that, didn't even know what a guarantor means). She had a surgery and was hospitalized for a week. Now the business department told me that the bill is going over 200k. There is no way my grandmother will be able to pay this. I just graduated from school and am currently unemployed. Will I be responsible for her medical bills??? Any suggestion will be helpful. Thank you.