You will need to get an X-ray and get it treated or removed depending on the findings. It sounds like an infected tooth where the infection has spread to the lymph nodes. In the meantime, till you can see a dentist you may need a course of antibiotics. Please call a dentist for a prescription.
Next Steps
Call a dentist for the medication and visit as soon as you can
Health Tips
Cold compress from outside the mouth may help.
warm saline mouth rinses may help
Apart from painkillers do not take any other medications till you have spoken to a dentist