It would help to know more details of how your finger came to be infected and what your symptoms are. I would go into the garden and pick some Calendula daisy flowers, chop these up finely so that I had a third of a cupful. Top it up with boiling water and allow to cool. Soak your finger in that for a few minutes several times a day and it will be soothed, the inflammation and pain will go and any pustular infections will be washed away. Repeat daily as required.
Alternatively, you can paint your finger with a cotton bud using 6 volume Hydrogen Peroxide from your Pharmacist. Tip a small amount of the undiluted Peroxide into a a saucer and use that - don't dip the bud in your bottle of pure peroxide - or try to tip the unused amount back into the bottle. That stops the infection in it's tracks and allows normal healing to proceed without the risk of reinfection.