Dental abscesses. Need help with how dangerous this is please!?

I lost a huge filling on my farthest top back tooth. It had a root canal 7 years ago. When I lost the filling a few months ago, it didn't hurt, until the past few weeks. I can feel the little screw in there from the work that was done before..Food is getting caught in that 1 tooth. I now have to pick it out (sorry that is GROSS, but it's necessary). The dentist at the time told me I had several abscesses beginning to form. Hot and cold food absolutely kills me now on my left side. Also 1 or 2 of the farthest back bottom teeth have some type of abscess too. I believe they all had root canals, but I'm not positive. I am on disability and I did not and do not have the money to fix this problem. It was never painful before, but now I am close to being in agony and I am eating Advil and Tylenol with Codeine to try and keep the pain at bay. It's not working, but it's better than nothing. My friend told me if I didn't take care of it...I could die from sepsis from the abscesses. I have not been feeling well and now my jaw feels hot and it's getting harder to chew or put anything hot or cold in my mouth as the pain is unbearable if I do. I know I must see a dentist, the money is the problem. Is it true I could die from leaving the abscess too long? I'm terrified I will lose my teeth. I also have tiny abscesses on the other side too (the dentist told me that about 7 months ago). All of these abscesses started after I had all my mercury fillings taken out and the dentist at the time, knew I had an acidity problem.but I spent thousands of dollars to get my whole mouth fixed. My new dentist said it was wrong for that dentist to have put the white fillings in because there is erosion at the gumline which he feels has started the infections. I live in Canada. I don't know what to do as I am sure this will cost several thousands of dollars again.The pain is getting much worse, I'm afraid I could die, afraid I'll lose my teeth (I do take care of them other than this). Can I die from this or is it just that it's painful and I have to deal with the pain until I get enough money? My jawbone itself is beginning to be very painful and it's hard for me to even open my mouth or move my jaw back and forth. It almost feels like I have a fever in my jawbone, as weird as that may sound. The pain has just started to shoot down from my jaw down through my glands in my throat on the same side as the abscesses. If you are a professional, can you please help me to know just how serious this is? Is it just pain or an infection that can cause me great harm? Thank you very much for your advise.
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If you do not take care of this problem you will 100% for sure lose you teeth. I know, I did not take care of my teeth for years and I have lost 4 teeth. I would get root canals, not get the crowns and then be in pain all over again. The abscess is dangerous. Quite possibly fatal. I don't know what dental is like in Canada, I thought it was better than in the USA. You absolutely must find a dentist and get these problems fixed. It has taken me 3 years and my dentist has prioritized my problems and has fixed them according to my insurance. It is a long process but I have not been in pain for over a year. You must take care of your teeth. They are the only teeth you have.
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