thanks for sharing your concern
You have developed an infection that has led to abscess
and draining sinus tract.
the steel rod you are talking about is called post and core. this is done to save a tooth when very little tooth structure is left, by endodontic treatment.
i would recommend you to visit your dentist
get an x ray done to see the infection.
accordingly treatment modalities can be suggested.
for now you can start with anti biotic and analgesic
. Cap NOVAMOX
1 OD for 03 days. IBUPROFEN
for 03 days
do warm saline rinses to reduce infection.
hope this helps