Do I have a case & how do I proceed?

On Dec 18th while eating at Taco Bell with my son, I felt a lot of pain on my gums. I spit out a staple that was in my tostada! I told the Manager. He said they don't have staples there. I told him that I didn't put it in there & I took a picture of it next to the food. He gave me the meal for free & took my name & number. Besides the fact it cut my gums, made them bleed, caused a sore & got stuck in my tooth, I didn't think too much about it with Christmas in a few days. However, the tooth it went into had an old filling & a week later started to crumble apart! Now pieces of my tooth are all falling out, half if it is already gone & it's painful to eat! I can't afford to go to the dentist & get it fixed! I'm a single mom with 3 teen boys! I need help with an attorney to get this fixed & compensated for!