How can I fix my broken finger?

Xray and MD. Proper diagnosis and treatment (splint, tape, or possible surgery) may be necessary for best long-term outcome. Self-diagnosis and non-treatment often leads to permanent loss of function and later arthritis problems in the damaged digit. The person who treats themself has a fool for a patient.
Finger fracture. Depends on the site and severity of the fracture, and whether or not the fractured bone has penetrated the skin. Fractures can be from trivial to severe and usually require a doctor to make an examination to determine the optimal treatment for the patient.