The yellow-green color, indicates that a collection of pus has formed under
the skin (called an abscess
). If this is the case it may require an incision and drainage.
Warm soaks in a mixture of 50% warm water and 50% liquid antibacterial soap 3-4 times daily for about 15 minutes.
In extreme cases, infection can move under the fingernail and need partial or complete nail removal. In your case there there does seem to be some cellulitis, involved and probably requires antibiotics.