About the only chance of reaching the infection at the root end of the tooth would be laser treatments, and that along with anything else would be iffy at best. The infection is in the root of the tooth, then can travel to other parts of the body to create more problems. Check out this tooth meridian chart.
My opinion is to have the tooth removed. Beg, borrow, or steal to have it done because your problems can multiply quickly.
So will the costs that you can't afford. Every tooth is connected to some other organ, or body part.