Tooth infection. Can't afford office visit. Have Doxycycline Mono (unexpired) from previous doc visit. Could this help until able to afford visit?

See a doctor. or call your dentist to call in antibiotics. Doxycycline will not be first line for serious dental infection.
Not recommended. A free or low-cost dentist can often be found at your local dental clinic. Please locate the nearest local dental society for more information. free dental care is usually only accessible to the truly needy. A tooth abscess requires a dentist's care and abscess tooth self-treatment is not recommended.
Suggest. I suggest you go to an emergency room and ask their assistance. An infected tooth can cause other issues as well and you need to be seen properly. Hope things improve for you.
Yes but. generally speaking doxy is a good antibiotic but it have been used by a lot of people as prophylactic from malaria and that might make it a weak antibiotics for active infection you need to take it twice a day and with meals if you felt the infection getting worst go to a regular doctor he might prescribed stronger antibiotic good luck.
Unlikely. Doxycycline can eventually help with gum infection; unlikely to help with tooth infection(abscess). Penicillin or amoxicillin are better choices.
No. That antibiotic is not used to treat dental infections. This cannot wait months or years, it needs to be treated now. Many offices have financing. You'll need to call around in your town to see where you might get some assistance.